bzoj 1296: [SCOI2009]粉刷匠

思路：两次dp， 第一次行内， 第二次行间， 刚开始读错题。。要死了。

#include<bits/stdc++.h>
#define LL long long
#define fi first
#define se second
#define mk make_pair
#define pii pair<int,int>
#define piii pair<int, pair<int,int>>

using namespace std;

const int N = 50 + 7;
const int M = 1e4 + 7;
const int inf = 0x3f3f3f3f;
const LL INF = 0x3f3f3f3f3f3f3f3f;
const int mod = 1e9 + 7;

char s[N][N];
int f[N][N][2], dp[N][2501], v[N][N], n, m, t;
int main() {
    scanf("%d%d%d", &n, &m, &t);
    for(int i = 1; i <= n; i++)
        scanf("%s", s[i] + 1);

    for(int k = 1; k <= n; k++) {
        memset(f, 0, sizeof(f));
        for(int i = 1; i <= m; i++) {
            for(int j = 1; j <= m; j++) {
                f[i][j][0] = f[i - 1][j][0];
                f[i][j][1] = f[i - 1][j][1];

                if(s[k][i] == '1') {
                    f[i][j][1] = max(f[i][j][1], f[i - 1][j][1] + 1);
                    f[i][j][1] = max(f[i][j][1], f[i - 1][j - 1][0] + 1);
                } else {
                    f[i][j][0] = max(f[i][j][0], f[i - 1][j][0] + 1);
                    f[i][j][0] = max(f[i][j][0], f[i - 1][j - 1][1] + 1);
                }
            }

        }
        for(int j = 1; j <= m; j++) {
            v[k][j] = max(f[m][j][0], f[m][j][1]);
            v[k][j] = max(v[k][j], v[k][j - 1]);
        }
    }

    int ans = 0;
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= t; j++) {
            for(int k = 0; k <= m && j - k >= 0; k++) {
                dp[i][j] = max(dp[i][j], dp[i - 1][j - k] + v[i][k]);
            }
            ans = max(ans, dp[i][j]);
        }
    }

    printf("%d
", ans);
    return 0;
}

/*
*/