I’m stuck!

问题描述

给定一个R行C列的地图，地图的每一个方格可能是'#', '+', '-', '|', '.', 'S', 'T'七个字符中的一个，分别表示如下意思：

'#': 任何时候玩家都不能移动到此方格；

'+': 当玩家到达这一方格后，下一步可以向上下左右四个方向相邻的任意一个非'#'方格移动一格；

'-': 当玩家到达这一方格后，下一步可以向左右两个方向相邻的一个非'#'方格移动一格；

'|': 当玩家到达这一方格后，下一步可以向上下两个方向相邻的一个非'#'方格移动一格；

'.': 当玩家到达这一方格后，下一步只能向下移动一格。如果下面相邻的方格为'#'，则玩家不能再移动；

'S': 玩家的初始位置，地图中只会有一个初始位置。玩家到达这一方格后，下一步可以向上下左右四个方向相邻的任意一个非'#'方格移动一格；

'T': 玩家的目标位置，地图中只会有一个目标位置。玩家到达这一方格后，可以选择完成任务，也可以选择不完成任务继续移动。如果继续移动下一步可以向上下左右四个方向相邻的任意一个非'#'方格移动一格。

此外，玩家不能移动出地图。

请找出满足下面两个性质的方格个数：

1. 玩家可以从初始位置移动到此方格；

2. 玩家不可以从此方格移动到目标位置。

输入格式

输入的第一行包括两个整数R 和C，分别表示地图的行和列数。(1 ≤ R, C ≤ 50)。

接下来的R行每行都包含C个字符。它们表示地图的格子。地图上恰好有一个'S'和一个'T'。

输出格式

如果玩家在初始位置就已经不能到达终点了，就输出“I'm stuck!”（不含双引号）。否则的话，输出满足性质的方格的个数。

样例输入

5 5

--+-+

..|#.

..|##

S-+-T

####.

样例输出

2

样例说明

如果把满足性质的方格在地图上用'X'标记出来的话，地图如下所示：

--+-+

..|#X

..|##

S-+-T

####X

该代码得分八十，剩下二十分不知道错在哪里。(再下面有AC代码）

#include <stdio.h>#include <stdlib.h>#include <stdbool.h>#define SIZE 3000typedef struct node{    int x;    int y;    char situation;} node;typedef struct queue{    node array[SIZE];    int head;    int rear;    int count;} queue;void enqueue(queue* ptr, node move);node dequeue(queue* ptr);bool isempty(queue* ptr);void mark_footstep(node start, int** matrix);bool isstuck(node start);char** maze;int r, c;node destination;int main(int argc, const char * argv[]) {    int i, j, count = 0;    int** matrix;    node start, temp;    scanf("%d %d", &r, &c);    maze = (char**)calloc(r, sizeof(char*));    matrix = (int**)calloc(r, sizeof(int*));    for(i = 0; i < r; i++){        maze[i] = (char*)calloc(c, sizeof(char));        matrix[i] = (int*)calloc(c, sizeof(int));    }    for(i = 0; i < r; i++){        getchar();        for(j = 0; j < c; j++){            maze[i][j] = getchar();            if(maze[i][j] == 'S'){                start.x = i;                start.y = j;                start.situation = 'S';            }            else if(maze[i][j] == 'T'){                destination.x = i;                destination.y = j;                destination.situation = 'T';            }        }    }    if(isstuck(start)){        puts("I'm stuck!");    }    else{        mark_footstep(start, matrix);        matrix[start.x][start.y] = 0;        matrix[destination.x][destination.y] = 0;        for(i = 0; i < r; i++){            for(j = 0; j < c; j++){                if(matrix[i][j]){                    temp.x = i;                    temp.y = j;                    temp.situation = maze[i][j];                    if(isstuck(temp)){                        count++;                    }                }            }        }        printf("%d\n", count);    }    for(i = 0; i < r; i++){        free(maze[i]);        free(matrix[i]);    }    free(maze);    free(matrix);    return 0;}void enqueue(queue* ptr, node move){    ptr->array[ptr->rear] = move;    ptr->rear = (ptr->rear + 1) % SIZE;    (ptr->count)++;}node dequeue(queue* ptr){    node temp = ptr->array[ptr->head];    ptr->head = (ptr->head + 1) % SIZE;    (ptr->count)--;    return temp;}bool isempty(queue* ptr){    if(!(ptr->count)){        return true;    }    else{        return false;    }}void mark_footstep(node start, int** matrix){    char situation;    node temp = start, next;    queue* q = (queue*)calloc(1, sizeof(queue));    int i, x, y;    int** visited = (int**)calloc(r, sizeof(int*));    for(i = 0; i < r; i++){        visited[i] = (int*)calloc(c, sizeof(int));    }    enqueue(q, temp);    while(!isempty(q)){        temp = dequeue(q);        visited[temp.x][temp.y] = matrix[temp.x][temp.y] = 1;        x = temp.x;        y = temp.y;        if(temp.situation == 'S' || temp.situation == '+' || temp.situation == 'T'){            if(y + 1 < c && (situation = maze[x][y + 1]) != '#' && !visited[x][y + 1]){                next.x = x;                next.y = y + 1;                next.situation = situation;                enqueue(q, next);            }            if(y - 1 >= 0 && (situation = maze[x][y - 1]) != '#' && !visited[x][y - 1]){                next.x = x;                next.y = y - 1;                next.situation = situation;                enqueue(q, next);            }            if(x + 1 < r && (situation = maze[x + 1][y]) != '#' && !visited[x + 1][y]){                next.x = x + 1;                next.y = y;                next.situation = situation;                enqueue(q, next);            }            if(x - 1 >= 0 && (situation = maze[x - 1][y]) != '#' && !visited[x - 1][y]){                next.x = x - 1;                next.y = y;                next.situation = situation;                enqueue(q, next);            }        }        else if(temp.situation == '-'){            if(y + 1 < c && (situation = maze[x][y + 1]) != '#' && !visited[x][y + 1]){                next.x = x;                next.y = y + 1;                next.situation = situation;                enqueue(q, next);            }            if(y - 1 >= 0 && (situation = maze[x][y - 1]) != '#' && !visited[x][y - 1]){                next.x = x;                next.y = y - 1;                next.situation = situation;                enqueue(q, next);            }        }        else if(temp.situation == '|'){            if(x + 1 < r && (situation = maze[x + 1][y]) != '#' && !visited[x + 1][y]){                next.x = x + 1;                next.y = y;                next.situation = situation;                enqueue(q, next);            }            if(x - 1 >= 0 && (situation = maze[x - 1][y]) != '#' && !visited[x - 1][y]){                next.x = x - 1;                next.y = y;                next.situation = situation;                enqueue(q, next);            }        }        else if(temp.situation == '.'){            if(x + 1 < r && (situation = maze[x + 1][y]) != '#' && !visited[x + 1][y]){                next.x = x + 1;                next.y = y;                next.situation = situation;                enqueue(q, next);            }        }    }    for(i = 0; i < r; i++){        free(visited[i]);    }    free(visited);}bool isstuck(node start){    node temp = start, next;    char situation;    int i, x, y;    queue* q = (queue*)calloc(1, sizeof(queue));    int** visited = (int**)calloc(r, sizeof(int*));    for(i = 0; i < r; i++){        visited[i] = (int*)calloc(c, sizeof(int));    }    enqueue(q, temp);    while(!isempty(q)){        temp = dequeue(q);        visited[temp.x][temp.y] = 1;        x = temp.x;        y = temp.y;        if(temp.situation == 'T'){            return false;        }        else if(temp.situation == 'S' || temp.situation == '+'){            if(y + 1 < c && (situation = maze[x][y + 1]) != '#' && !visited[x][y + 1]){                next.x = x;                next.y = y + 1;                next.situation = situation;                enqueue(q, next);            }            if(y - 1 >= 0 && (situation = maze[x][y - 1]) != '#' && !visited[x][y - 1]){                next.x = x;                next.y = y - 1;                next.situation = situation;                enqueue(q, next);            }            if(x + 1 < r && (situation = maze[x + 1][y]) != '#' && !visited[x + 1][y]){                next.x = x + 1;                next.y = y;                next.situation = situation;                enqueue(q, next);            }            if(x - 1 >= 0 && (situation = maze[x - 1][y]) != '#' && !visited[x - 1][y]){                next.x = x - 1;                next.y = y;                next.situation = situation;                enqueue(q, next);            }        }        else if(temp.situation == '-'){            if(y + 1 < c && (situation = maze[x][y + 1]) != '#' && !visited[x][y + 1]){                next.x = x;                next.y = y + 1;                next.situation = situation;                enqueue(q, next);            }            if(y - 1 >= 0 && (situation = maze[x][y - 1]) != '#' && !visited[x][y - 1]){                next.x = x;                next.y = y - 1;                next.situation = situation;                enqueue(q, next);            }        }        else if(temp.situation == '|'){            if(x + 1 < r && (situation = maze[x + 1][y]) != '#' && !visited[x + 1][y]){                next.x = x + 1;                next.y = y;                next.situation = situation;                enqueue(q, next);            }            if(x - 1 >= 0 && (situation = maze[x - 1][y]) != '#' && !visited[x - 1][y]){                next.x = x - 1;                next.y = y;                next.situation = situation;                enqueue(q, next);            }        }        else if(temp.situation == '.'){            if(x + 1 < r && (situation = maze[x + 1][y]) != '#' && !visited[x + 1][y]){                next.x = x + 1;                next.y = y;                next.situation = situation;                enqueue(q, next);            }        }    }        for(i = 0; i < r; i++){        free(visited[i]);    }    free(visited);    free(q);    return true;}

下面是AC代码。上面的代码算法没有错误，只是在广度优先搜索的时候错误地在出队的时候标记该点已访问。实际上，深度优先搜索时一定要在入队时就把该点标记为已访问，否则可能会把一个点重复入队。

#include <stdio.h>#include <stdlib.h>#include <stdbool.h>#define SIZE 3000typedef struct node{    int x;    int y;    char situation;} node;typedef struct queue{    node array[SIZE];    int head;    int rear;    int count;} queue;void enqueue(queue* ptr, node move);node dequeue(queue* ptr);bool isempty(queue* ptr);void mark_footstep(node start, int** matrix);bool isstuck(node start);char** maze;int r, c;node destination;int main(int argc, const char * argv[]) {    int i, j, count = 0;    int** matrix;    node start, temp;    scanf("%d %d", &r, &c);    maze = (char**)calloc(r, sizeof(char*));    matrix = (int**)calloc(r, sizeof(int*));    for(i = 0; i < r; i++){        maze[i] = (char*)calloc(c, sizeof(char));        matrix[i] = (int*)calloc(c, sizeof(int));    }    for(i = 0; i < r; i++){        getchar();        for(j = 0; j < c; j++){            maze[i][j] = getchar();            if(maze[i][j] == 'S'){                start.x = i;                start.y = j;                start.situation = 'S';            }            else if(maze[i][j] == 'T'){                destination.x = i;                destination.y = j;                destination.situation = 'T';            }        }    }    if(isstuck(start)){        puts("I'm stuck!");    }    else{        mark_footstep(start, matrix);        matrix[start.x][start.y] = 0;        matrix[destination.x][destination.y] = 0;        for(i = 0; i < r; i++){            for(j = 0; j < c; j++){                if(matrix[i][j]){                    temp.x = i;                    temp.y = j;                    temp.situation = maze[i][j];                    if(isstuck(temp)){                        count++;                    }                }            }        }        printf("%d\n", count);    }    for(i = 0; i < r; i++){        free(maze[i]);        free(matrix[i]);    }    free(maze);    free(matrix);    return 0;}void enqueue(queue* ptr, node move){    ptr->array[ptr->rear] = move;    ptr->rear = (ptr->rear + 1) % SIZE;    (ptr->count)++;}node dequeue(queue* ptr){    node temp = ptr->array[ptr->head];    ptr->head = (ptr->head + 1) % SIZE;    (ptr->count)--;    return temp;}bool isempty(queue* ptr){    if(!(ptr->count)){        return true;    }    else{        return false;    }}void mark_footstep(node start, int** matrix){    char situation;    node temp = start, next;    queue* q = (queue*)calloc(1, sizeof(queue));    int i, x, y;    int** visited = (int**)calloc(r, sizeof(int*));    for(i = 0; i < r; i++){        visited[i] = (int*)calloc(c, sizeof(int));    }    enqueue(q, temp);    while(!isempty(q)){        temp = dequeue(q);        visited[temp.x][temp.y] = matrix[temp.x][temp.y] = 1;        x = temp.x;        y = temp.y;        if(temp.situation == 'S' || temp.situation == '+' || temp.situation == 'T'){            if(y + 1 < c && (situation = maze[x][y + 1]) != '#' && !visited[x][y + 1]){                next.x = x;                next.y = y + 1;                next.situation = situation;                enqueue(q, next);                visited[next.x][next.y] = matrix[next.x][next.y] = 1;            }            if(y - 1 >= 0 && (situation = maze[x][y - 1]) != '#' && !visited[x][y - 1]){                next.x = x;                next.y = y - 1;                next.situation = situation;                enqueue(q, next);                visited[next.x][next.y] = matrix[next.x][next.y] = 1;            }            if(x + 1 < r && (situation = maze[x + 1][y]) != '#' && !visited[x + 1][y]){                next.x = x + 1;                next.y = y;                next.situation = situation;                enqueue(q, next);                visited[next.x][next.y] = matrix[next.x][next.y] = 1;            }            if(x - 1 >= 0 && (situation = maze[x - 1][y]) != '#' && !visited[x - 1][y]){                next.x = x - 1;                next.y = y;                next.situation = situation;                enqueue(q, next);                visited[next.x][next.y] = matrix[next.x][next.y] = 1;            }        }        else if(temp.situation == '-'){            if(y + 1 < c && (situation = maze[x][y + 1]) != '#' && !visited[x][y + 1]){                next.x = x;                next.y = y + 1;                next.situation = situation;                enqueue(q, next);                visited[next.x][next.y] = matrix[next.x][next.y] = 1;            }            if(y - 1 >= 0 && (situation = maze[x][y - 1]) != '#' && !visited[x][y - 1]){                next.x = x;                next.y = y - 1;                next.situation = situation;                enqueue(q, next);                visited[next.x][next.y] = matrix[next.x][next.y] = 1;            }        }        else if(temp.situation == '|'){            if(x + 1 < r && (situation = maze[x + 1][y]) != '#' && !visited[x + 1][y]){                next.x = x + 1;                next.y = y;                next.situation = situation;                enqueue(q, next);                visited[next.x][next.y] = matrix[next.x][next.y] = 1;            }            if(x - 1 >= 0 && (situation = maze[x - 1][y]) != '#' && !visited[x - 1][y]){                next.x = x - 1;                next.y = y;                next.situation = situation;                enqueue(q, next);                visited[next.x][next.y] = matrix[next.x][next.y] = 1;            }        }        else if(temp.situation == '.'){            if(x + 1 < r && (situation = maze[x + 1][y]) != '#' && !visited[x + 1][y]){                next.x = x + 1;                next.y = y;                next.situation = situation;                enqueue(q, next);                visited[next.x][next.y] = matrix[next.x][next.y] = 1;            }        }    }    for(i = 0; i < r; i++){        free(visited[i]);    }    free(visited);}bool isstuck(node start){    node temp = start, next;    char situation;    int i, x, y;    queue* q = (queue*)calloc(1, sizeof(queue));    int** visited = (int**)calloc(r, sizeof(int*));    for(i = 0; i < r; i++){        visited[i] = (int*)calloc(c, sizeof(int));    }    enqueue(q, temp);    visited[temp.x][temp.y] = 1;    while(!isempty(q)){        temp = dequeue(q);        x = temp.x;        y = temp.y;        if(temp.situation == 'T'){            return false;        }        else if(temp.situation == 'S' || temp.situation == '+'){            if(y + 1 < c && (situation = maze[x][y + 1]) != '#' && !visited[x][y + 1]){                next.x = x;                next.y = y + 1;                next.situation = situation;                enqueue(q, next);                visited[next.x][next.y] = 1;            }            if(y - 1 >= 0 && (situation = maze[x][y - 1]) != '#' && !visited[x][y - 1]){                next.x = x;                next.y = y - 1;                next.situation = situation;                enqueue(q, next);                visited[next.x][next.y] = 1;            }            if(x + 1 < r && (situation = maze[x + 1][y]) != '#' && !visited[x + 1][y]){                next.x = x + 1;                next.y = y;                next.situation = situation;                enqueue(q, next);                visited[next.x][next.y] = 1;            }            if(x - 1 >= 0 && (situation = maze[x - 1][y]) != '#' && !visited[x - 1][y]){                next.x = x - 1;                next.y = y;                next.situation = situation;                enqueue(q, next);                visited[next.x][next.y] = 1;            }        }        else if(temp.situation == '-'){            if(y + 1 < c && (situation = maze[x][y + 1]) != '#' && !visited[x][y + 1]){                next.x = x;                next.y = y + 1;                next.situation = situation;                enqueue(q, next);                visited[next.x][next.y] = 1;            }            if(y - 1 >= 0 && (situation = maze[x][y - 1]) != '#' && !visited[x][y - 1]){                next.x = x;                next.y = y - 1;                next.situation = situation;                enqueue(q, next);                visited[next.x][next.y] = 1;            }        }        else if(temp.situation == '|'){            if(x + 1 < r && (situation = maze[x + 1][y]) != '#' && !visited[x + 1][y]){                next.x = x + 1;                next.y = y;                next.situation = situation;                enqueue(q, next);                visited[next.x][next.y] = 1;            }            if(x - 1 >= 0 && (situation = maze[x - 1][y]) != '#' && !visited[x - 1][y]){                next.x = x - 1;                next.y = y;                next.situation = situation;                enqueue(q, next);                visited[next.x][next.y] = 1;            }        }        else if(temp.situation == '.'){            if(x + 1 < r && (situation = maze[x + 1][y]) != '#' && !visited[x + 1][y]){                next.x = x + 1;                next.y = y;                next.situation = situation;                enqueue(q, next);                visited[next.x][next.y] = 1;            }        }    }        for(i = 0; i < r; i++){        free(visited[i]);    }    free(visited);    free(q);    return true;}