杭电OJ 1026：Ignatius and the Princess I

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比较麻烦的一道题目，自己刚开始思路不清楚，错了很多次，后来看了别人的解答，才找出错误的地方。

#include <iostream>#include <queue>#include <stack>#include <fstream>using namespace std;int dir[][2] = {{-1,0},{1,0},{0,-1},{0,1}};typedef struct node {int i, j;int time;friend bool operator<(node n1, node n2)//按照时间大小从小到大排列{return n1.time > n2.time;}}Node;typedef struct {int i;int j;}Point;char map[100][100];//记录整个地图bool used[100][100];//标记是否已经搜索过Point result[100][100];//记录达到某一点的前一个位置，通过回溯找到路径int n, m;//表示地图的大小int bfs()//广度搜索，返回到达终点的最小时间数值{priority_queue<Node> Q;//优先级队列Node start;start.i = 0;start.j = 0;start.time = 0;Point tempP;tempP.i = -1;tempP.j = -1;result[0][0] = tempP;used[0][0] = true;Q.push(start);while(!Q.empty()){Node tempN = Q.top();Q.pop();for (int k = 0; k < 4;  ++ k){int ni = tempN.i + dir[k][0];int nj = tempN.j + dir[k][1];if (ni >= 0 && ni < n && nj >= 0 && nj < m && !used[ni][nj] && map[ni][nj] != 'X'){Node temp;temp.i = ni;temp.j = nj;if (map[ni][nj] == '.')temp.time = tempN.time + 1;elsetemp.time = tempN.time + map[ni][nj] - '0' + 1;used[ni][nj] = true;Point tp;tp.i = tempN.i;tp.j = tempN.j;result[ni][nj] = tp;if (ni == n - 1 && nj == m - 1)return temp.time;Q.push(temp);}}}return -1;}int main (){while (cin >> n >> m){for (int i = 0; i < n ; ++ i)for (int j = 0; j < m ; ++ j){cin>>map[i][j];used[i][j] = false;}int t = bfs();if (t == -1){cout<<"God please help our poor hero."<<endl;cout <<"FINISH"<<endl;}if (t != -1){cout <<"It takes "<<t<<" seconds to reach the target position, let me show you the way."<<endl;stack<Point> path;Point pp ;pp.i = n - 1;pp.j = m - 1;path.push(pp);while (result[pp.i][pp.j].i != -1 && result[pp.i][pp.j].j != -1){path.push(result[pp.i][pp.j]);pp = result[pp.i][pp.j];}int time = 1;pp = path.top();path.pop();while(!path.empty()){cout << time<<"s:("<<pp.i<<","<<pp.j<<")->("<<path.top().i<<","<<path.top().j<<")"<<endl;time ++;if (map[path.top().i][path.top().j] != '.'){int tt = map[path.top().i][path.top().j] - '0';for (int mm = 0; mm < tt; ++ mm){cout <<time<<"s:FIGHT AT ("<<path.top().i<<","<<path.top().j<<")"<<endl;time ++;}}pp = path.top();path.pop();}cout <<"FINISH"<<endl;}}return 0;}

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