HDU 3683

来源：互联网发布：广州新百佳网络批发编辑：程序博客网时间：2024/05/16 09:42

因为少了一句if，这个AC迟来了一年...
解法：假设A先手，B后手。
    1.如果A有必胜点，放下去即连成5个，那么A一步获胜。
    2.如果B有两个以上的必胜点，那么B两步必胜。
    3.如果B只有一个必胜点，那么A第一步肯定放在B的必胜点上。再判断A是否有两个以上的必胜点，如果有，A三步获胜。
    4.枚举A第一步的走法，如果能走出两个以上的必胜点，那么A三步获胜。
    5.如果以上情况都不成立，那三步之内没人可以获胜。

#include <iostream>using namespace std;struct POINT{    int x, y;};int n, white, black;int player, other;int map[15][15];int dir[4][2] = {{0, 1}, {1, 0}, {1, 1}, {1, -1}};char str[][10] = {"", "white", "black"};bool ReadCase(){    int i, col;    POINT tmp;    scanf("%d", &n);    if (n == 0)    {        return false;    }    memset(map, 0, sizeof(map));    white = black = 0;    for (i = 0; i < n; i++)    {        scanf("%d %d %d", &tmp.x, &tmp.y, &col);        if (col == 0)        {            white++;            map[tmp.x][tmp.y] = 1;        }        else        {            black++;            map[tmp.x][tmp.y] = 2;        }    }    return true;}bool Check(){    if (black == white)    {        player = 2;        other = 1;    }    else if (black == white + 1)    {        player = 1;        other = 2;    }    else    {        return false;    }    return true;}bool Bound(POINT p){    return p.x >= 0 && p.x <= 14 && p.y >= 0 && p.y <= 14;}int GetMaxLength(POINT p, int c){    int res = 0;    for (int i = 0; i < 4; i++)    {        int len = 0;        POINT tmp = p;        while (true)        {            tmp.x = tmp.x + dir[i][0];            tmp.y = tmp.y + dir[i][1];            if (!Bound(tmp) || map[tmp.x][tmp.y] != c)            {                break;            }            len++;        }        tmp = p;        while (true)        {            tmp.x = tmp.x - dir[i][0];            tmp.y = tmp.y - dir[i][1];            if (!Bound(tmp) || map[tmp.x][tmp.y] != c)            {                break;            }            len++;        }        len++;        if (len > res)        {            res = len;        }    }    return res;}int GetWinPoint(POINT &p, int c){    int num = 0;    for (int i = 0; i < 15; i++)    {        for (int j = 0; j < 15; j++)        {            POINT tmp;            tmp.x = i;            tmp.y = j;            int a = 0;            if (map[tmp.x][tmp.y] == 0 && (a = GetMaxLength(tmp, c)) >= 5)            {                num++;                if (num == 1)                {                    p = tmp;                }            }            //cout << a << endl;        }    }    return num;}void Solve(){    if (!Check())    {        printf("Invalid.\n");        return;    }    POINT p, p2;    int num;    if (GetWinPoint(p, player) >= 1)    {        printf("Place %s at (%d,%d) to win in 1 move.\n", str[player], p.x, p.y);        return;    }    if ((num = GetWinPoint(p, other)) >= 2)    {        printf("Lose in 2 moves.\n");        return;    }    if (num == 1)    {        map[p.x][p.y] = player;        if (GetWinPoint(p2, player) >= 2)        {            printf("Place %s at (%d,%d) to win in 3 moves.\n", str[player], p.x, p.y);            return;        }    }    else    {        for (int i = 0; i < 15; i++)        {            for (int j = 0; j < 15; j++)            {                if (map[i][j] == 0)                {                    map[i][j] = player;                    if (GetWinPoint(p2, player) >= 2)                    {                        printf("Place %s at (%d,%d) to win in 3 moves.\n", str[player], i, j);                        return;                    }                    map[i][j] = 0;                }            }        }    }    printf("Cannot win in 3 moves.\n");}int main(){    while (ReadCase())    {        Solve();    }    return 0;}