DP

PS: 记忆化搜索

#include <iostream>#include <cstdio>#include <algorithm>#include <cstring>using namespace std;const int N = 105;const int INF = 0x3fffffff;char str[N];int dp[N][N];int path[N][N];bool done[N][N];using namespace std;int bracket(int i, int j) {    if(done[i][j]) return dp[i][j];    int ans = INF;    if(i > j) return 0;    else if(i==j) return 1;    else {        if((str[i]=='('&&str[j]==')') || (str[i]=='['&&str[j]==']')) {            ans = min(ans, bracket(i+1, j-1));        }        if(str[i]=='('||str[i]=='[') {            ans = min(ans, bracket(i+1, j)+1);        }        if(str[j]==')'||str[j]==']') {            ans = min(ans, bracket(i, j-1)+1);        }        for(int k = i; k < j; k++) {            ans = min(ans, bracket(i, k)+bracket(k+1, j));        }    }    done[i][j] = true;    return dp[i][j] = ans;}int main(){    while(gets(str))    {        memset(done, false, sizeof(done));        int n = strlen(str);        if(n==0) {            printf("\n");            continue;        }        int ans = bracket(0, n-1);        printf("%d\n", ans);    }    return 0;}/***(([)(]((]][]([(]((([])***/