Codeforces

https://codeforces.com/contest/1198/problem/D
原来是dp的思路，而且是每次切成两半向下递归。好像在哪里见过类似的，貌似是紫书的样子。
再想想好像就很显然的样子，并不会出现奇奇怪怪的合并的样子。

#include<bits/stdc++.h>
using namespace std;

const int INF = 0x3f3f3f3f;

int dp[51][51][51][51];
char g[51][51];

int main() {
#ifdef Yinku
    freopen("Yinku.in", "r", stdin);
#endif // Yinku
    int n;
    while(~scanf("%d", &n)) {
        for(int i = 1; i <= n; ++i)
            scanf("%s", g[i] + 1);
        for(int i = 1; i <= n; ++i) {
            for(int j = 1; j <= n; ++j) {
                dp[i][j][i][j] = (g[i][j] == '#');
            }
        }
        for(int h = 1; h <= n; ++h) {
            for(int w = 1; w <= n; ++w) {
                if(w == 1 && h == 1)
                    continue;
                for(int i = 1; i <= n; ++i) {
                    if(i + h - 1 > n)
                        break;
                    for(int j = 1; j <= n; ++j) {
                        if(j + w - 1 > n)
                            break;
                        int &tmp = dp[i][j][i + h - 1][j + w - 1] = max(h,w);
                        for(int k = i; k < i + h - 1; ++k) {
                            tmp = min(tmp, dp[i][j][k][j + w - 1] + dp[k + 1][j][i + h - 1][j + w - 1]);
                        }
                        for(int k = j; k < j + w - 1; ++k) {
                            tmp = min(tmp, dp[i][j][i + h - 1][k] + dp[i][k + 1][i + h - 1][j + w - 1]);
                        }
                    }
                }
            }
        }
        printf("%d
", dp[1][1][n][n]);
    }
}