40 lines
718 B
C++
40 lines
718 B
C++
#include<cstdio>
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#include<algorithm>
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using namespace std;
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const int maxn=110;
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int n,a[maxn],s[maxn];
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int f[maxn][maxn],g[maxn][maxn],d[maxn][maxn];
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int main()
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{
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#ifdef local
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freopen("pro.in","r",stdin);
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#endif
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while(scanf("%d",&n)==1&&n)
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{
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s[0]=0;
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for(int i=1;i<=n;i++) { scanf("%d",&a[i]); s[i]=s[i-1]+a[i]; }
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for(int i=1;i<=n;i++) f[i][i]=g[i][i]=d[i][i]=a[i];
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for(int L=1;L<n;L++)
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for(int i=1;i+L<=n;i++)
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{
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int j=i+L;
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int m=0;
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m=min(m,f[i+1][j]);
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m=min(m,g[i][j-1]);
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d[i][j]=s[j]-s[i-1]-m;
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f[i][j]=min(d[i][j],f[i+1][j]);
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g[i][j]=min(d[i][j],g[i][j-1]);
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}
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printf("%d\n",2*d[1][n]-s[n]);
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}
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return 0;
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}
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/*
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d[1][1]=4
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d[2][2]=-10
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d[3][3]=-20
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d[4][4]=7
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d[1][4]=-6
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*/
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