[Monotone queue] Hdu 3415 Max Sum of Max-k-sub-sequence

Test instructions

Give N and K, and give you n the number of rings formed

Ask you the maximum number of consecutive k and how much

And the output interval, and the same as the left end of the smallest, again the smallest length

Ideas:

We record prefixes and sum[i]

Open a monotonic queue maintain sum[i-1] with the lowest value

Because for the sum[i]-sum[j to the current position], the smaller the sum[j], the greater the sum[i]

So the maintenance is to the current position to meet the minimum requirements of the sun[j]

Code:

#include "cstdlib" #include "Cstdio" #include "CString" #include "Cmath" #include "queue" #include "algorithm" #include "    iostream "#include" map "using namespace std; #define N 222222int sum[n],v[n];int q[2*n];int main () {int t;    cin>>t;        while (t--) {int n,k;        scanf ("%d%d", &n,&k);        deque<int>q;        sum[0]=0;            for (int i=1;i<=n;i++) {scanf ("%d", &v[i]);        Sum[i]=sum[i-1]+v[i];        } for (int i=n+1;i<2*n;i++) sum[i]=sum[i-1]+v[i-n];        int ans=-999999999,x,y;        int top=0,ed=0;            for (int i=1;i<2*n;i++) {while (top<ed && sum[q[ed-1]]>=sum[i-1]) ed--;            Q[ed++]=i-1;            while (top<ed && i-q[top]>k) top++;            int Tep=sum[i]-sum[q[top]];                if (Tep>ans) {ans=tep;                x=q[top]+1;            Y=i;        }} if (Y>n) y-=n; printf ("%d%d%d\n", ans, x, y); } return 0;}

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[Monotone queue] Hdu 3415 Max Sum of Max-k-sub-sequence