B - Beautiful Numbers

Question is intended: to give you a n, and n random permutation of 1-n, which is selected from a sequence period, to make the sequence order is 1-m, m is the Beautiful Numbers, if 1-n is Beautiful Numbers the output 1,

Otherwise, output 0;

Thinking: will randomly arranged into an array of positions p, for example, a position corresponding to 3, p [1] = 3,2 corresponding to position 4, the p [2] = 4;

　　　Taken individually sequences array p, l always marked with a sequence start position, end position marker sequence R & lt always determines whether the r-l + 1 to the current i.

#include<bits/stdc++.h>
#define N 2e5+10
using namespace std;
int main(){
        int t,i,n,p[int(N)],a,l,r;
        while(~scanf("%d",&t)){
                while(t--){
                        memset(p,0,sizeof(p));
                        scanf("%d",&n);
                        for(i=1;i<=n;i++){
                                scanf("%d",&a);
                                p[a]=i;
                        }
                        l=r=p[1];
                        printf("1");
                        for(i=2;i<=n;i++){
                                l=min(l,p[i]);
                                r=max(r,p[i]);
                                if(r-l+1==i)
                                        printf("1");
                                else    printf("0");
                        }
                        printf("\n");
                }
        }
}

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