51Nod 1021 石子归并 (区间dp)

原题链接：https://www.51nod.com/Challenge/Problem.html#!#problemId=1021

#include 
using namespace std;
const int maxn = 110;
int dp[maxn][maxn];
int a[maxn];
int sum[maxn];
int n;

int Sum(int start, int end){
    return sum[end] - sum[start-1];
}

int main(){
    memset(dp,0x3f,sizeof(dp));
    memset(sum,0,sizeof(sum));

    scanf("%d",&n);
    for(int i=1;i<=n;i++){
        scanf("%d",&a[i]);
        sum[i] = sum[i-1] + a[i];
        dp[i][i] = 0;
    }
    for(int len = 1; len <= n; len ++){                         //枚举要合并的长度
        for(int start = 1; start+len-1 <= n; start ++){         //枚举起点
            int end = start + len - 1;                          //终点
            for(int k = start; k < end; k++){                   //枚举分割点
                dp[start][end] = min(dp[start][end], dp[start][k] + dp[k+1][end] + Sum(start,end));
            }
        }
    }
    printf("%d\n", dp[1][n]);

    return 0;
}