Submission #59979

#	Time	Username	Problem	Language	Result	Execution time	Memory
59979		baekjoon	공장 (KOI13_factory)	C++14	20 / 20	470 ms	8556 KiB

factory

#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;
int l;
void update(vector<int> &a, int i, int diff) {
    while (i <= l) {
        a[i] += diff;
        i += (i & -i);
    }
}
int sum(vector<int> &a, int i) {
    int ans = 0;
    while (i > 0) {
        ans += a[i];
        i -= (i & -i);
    }
    return ans;
}
int sum(vector<int> &a, int l, int r) {
    if (l > r) return 0;
    return sum(a, r) - sum(a, l-1);
}
int d[1000001];
int main() {
    int n;
    scanf("%d",&n);
    vector<int> a(n);
    for (int i=0; i<n; i++) {
        scanf("%d",&a[i]);
    }
    for (int i=0; i<n; i++) {
        int num;
        scanf("%d",&num);
        d[num] = i+1;
    }
    long long ans = 0;
    vector<int> tree(n+1);
    l = n;
    for (int i=0; i<n; i++) {
        ans += (long long)sum(tree, d[a[i]]+1, n);
        update(tree, d[a[i]], 1);
    }
    printf("%lld\n",ans);
    return 0;
}

Compilation message (stderr)

factory.cpp: In function 'int main()':
factory.cpp:27:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
     ~~~~~^~~~~~~~~
factory.cpp:30:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d",&a[i]);
         ~~~~~^~~~~~~~~~~~
factory.cpp:34:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d",&num);
         ~~~~~^~~~~~~~~~~

• Subtask 1: 2.2 / 2.2
• Subtask 2: 3.4 / 3.4
• Subtask 3: 3.8 / 3.8
• Subtask 4: 4.8 / 4.8
• Subtask 5: 5.8 / 5.8