Submission #239830

#	Time	Username	Problem	Language	Result	Execution time	Memory
239830		mhy908	Lasers (NOI19_lasers)	C++14	21 / 100	55 ms	7160 KiB

lasers

#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
#define eb emplace_back
using namespace std;
typedef long long LL;
int n, q;
struct FENWICK{
    int tree[500010];
    int sum(int i){
        int ans=0;
        while(i){
            ans+=tree[i];
            i-=(i&-i);
        }
        return ans;
    }
    void update(int i, int num){
        while(i<=500000){
            tree[i]+=num;
            i+=(i&-i);
        }
    }
}fen;
int arr[500010], sum[500010], ans;
int main(){
    scanf("%d %d", &n, &q);
    for(int i=1; i<=q; i++){
        int sz;
        scanf("%d", &sz);
        for(int j=1; j<=sz; j++){
            scanf("%d", &arr[j]);
            sum[j]=sum[j-1]+arr[j];
        }
        for(int j=1; j<=sz; j++){
            int e=sum[j], s=n-(sum[sz]-sum[j-1])+1;
            if(s<=e){
                fen.update(s, 1);
                fen.update(e+1, -1);
            }
        }
    }
    for(int i=1; i<=n; i++){
        if(fen.sum(i))ans++;
    }
    printf("%d", ans);
}

Compilation message (stderr)

lasers.cpp: In function 'int main()':
lasers.cpp:28:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &n, &q);
     ~~~~~^~~~~~~~~~~~~~~~~
lasers.cpp:31:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d", &sz);
         ~~~~~^~~~~~~~~~~
lasers.cpp:33:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d", &arr[j]);
             ~~~~~^~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 14
• Subtask 3: 0 / 20
• Subtask 4: 21 / 21
• Subtask 5: 0 / 22
• Subtask 6: 0 / 13