noip2006T1 能量項鏈

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     最近一直在做noip的題，由於太水一直沒有寫題解，可是這道題，這道題。啊啊啊啊……

     明明水的要命，調了一節課啊！！我乾脆不要搞OI了啊！

     特別逗比的錯誤啊！！！！

     代碼：

#include <cstdio>#include <cstring>#include <iostream>#include <cstdlib>#include <algorithm>#define N 251using namespace std;int n;int a[N][N];int val[N];int main(){    scanf("%d", &n);    memset(a, 0, sizeof(a));    for (int i = 1; i <= n; ++i)    {        int x; scanf("%d", &x);        val[i] = val[i+n] = x;    }        for (int j = 1; j < n; ++j)        for (int i = 1; i <= 2*n, i+j <= 2*n; ++i) // i  一定要到 2*n !!!!!            for (int k = i; k < i+j; ++k)                a[i][i+j] = max(a[i][i+j], a[i][k] + a[k+1][i+j] + val[i]*val[k+1]*val[i+j+1]);    int ans = 0;    for (int i = 1; i <= n; ++i)        ans = max(ans, a[i][i+n-1]);    printf("%d\n", ans);    return 0;}

 

noip2006T1 能量項鏈