Topcoder SRM 698 Div1 250 RepeatString(dp)

题意

[题目链接]这怎么发链接啊。。。。。

Sol

枚举一个断点，然后类似于LIS一样dp一波

这个边界条件有点迷啊。。fst了两遍。。。

#include<bits/stdc++.h>
using namespace std;
const int MAXN = 1e5 + 10, INF = 1e9 + 7;
inline int read() {
    char c = getchar(); int x = 0, f = 1;
    while(c < '0' || c > '9') {if(c == '-') f = -1; c = getchar();}
    while(c >= '0' && c <= '9') x = x * 10 + c - '0', c = getchar();
    return x * f;
}
int N, f[101][101];
class RepeatString{
public:
    int solve(int pos, string s) {
        string a, b; a += '.'; b += '*';
        memset(f, 0x3f, sizeof(f));
        for(int i = 0; i < pos; i++) a += s[i];
        for(int i = pos; i < N; i++)  b += s[i];

        int la = a.length() - 1, lb = b.length() - 1;
        f[0][0] = 0;
        for(int i = 0; i <= la; i++) f[i][0] = i;
        for(int i = 0; i <= lb; i++) f[0][i] = i;
        for(int i = 1; i <= la; i++) {
            for(int j = 1; j <= lb; j++) {
                f[i][j] = min(f[i - 1][j] + 1, f[i][j - 1] + 1);
                f[i][j] = min(f[i][j], f[i - 1][j - 1] + (a[i] != b[j]));
            }
        }
        return f[la][lb];
    }
    int minimalModify(string s) {
        N = s.length(); int ans = N;
        for(int i = 0; i < N; i++) ans = min(ans, solve(i, s));
        return ans;
    }
};

int main() {
    string s;
    cin >> s;
    cout << RepeatString().minimalModify(s);
}
/*
pkafkbeabccfjejkdgkaatcedaocgmecaapakfvbfgefr
*/