牛客多校训练09

牛客多校训练09

I. The Great Wall II

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#include <bits/stdc++.h>
using namespace std;

const int maxn=8010;

int a[maxn],dp[maxn][maxn];
int pre[maxn];

int main(){
    #ifdef lmj_debug
        freopen("1.in","r",stdin);
    #endif

    int n;
    scanf("%d",&n);
    for (int i=1;i<=n;i++) scanf("%d",&a[i]);
    memset(dp,0x3f,sizeof(dp));
    dp[0][0]=0;
    for (int i=1;i<=n;i++){
        pre[i]=0;
        for (int j=i-1;j>=1;j--){
            if(a[j]>a[i]) {
                pre[i]=j;
                break;
            }
        }
    }
    for (int j=1;j<=n;j++){
        stack< pair<int,int> >s;
        for (int i=1;i<=n;i++){
            int mi=dp[j-1][i-1];
            while(s.size() && s.top().first<=a[i]){
                mi=min(mi,s.top().second);
                s.pop();
            }
            dp[j][i]=min(dp[j][pre[i]],a[i]+mi);
            s.push({a[i],mi});
        }
    }
    for (int i=1;i<=n;i++){
        printf("%d\n",dp[i][n]);
    }
    return 0;
}