poj 3254 Corn Fields

状态DP

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define MOD 100000000
#define MAX  12
#define MAX_STATE (1 << 12)

int dp[MAX][MAX_STATE];
int map[MAX];        //存储土地的状态

int st[MAX_STATE];    //存储所有可能的状态

//非0，则该状态不符合
int judge(int s) {
    return (s&(s << 1));
}

//非0，则该状态不符合
int judgeState(int i, int s) {
    return (map[i] & st[s]);
}

int main()
{
    int M, N;
    int i, j, s, k;
    int ans;

    while (~scanf("%d %d", &M, &N)) {
        memset(dp, 0, sizeof(dp));
        memset(map, 0, sizeof(map));
        memset(st, 0, sizeof(st));

        //初始化map，将土地状态压缩
        int temp;
        for (i = 0; i < M; i++) {
            for (j = 0; j < N; j++) {
                scanf("%d", &temp);

                if (temp == 0) {
                    map[i] += (1 << j);
                }
            }
        }

        //初始化所有可能状态
        k = 0;
        for (s = 0; s < (1 << N); s++) {
            if (!judge(s)) {
                st[k++] = s;
            }
        }

        //初始化dp[0][]
        for (s = 0; s < k; s++) {
            if (!judgeState(0, s)) {
                dp[0][s] = 1;
            }
        }

        for (i = 1; i < M; i++) {
            for (j = 0; j < k; j++) {
                if (judgeState(i, j)) continue;
                for (s = 0; s < k; s++) {
                    if (judgeState(i - 1, s)) continue;

                    if (!(st[j] & st[s])) {
                        dp[i][j] += dp[i - 1][s];
                    }
                }
            }
        }

        ans = 0;
        for (s = 0; s < k; s++) {
            ans += dp[M - 1][s];
            ans = ans % MOD;
        }

        printf("%d
", ans);
    }
}