25 lines
389 B
C++
25 lines
389 B
C++
#include <bits/stdc++.h>
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#define endl '\n'
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using namespace std;
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int n, k, cnt = 0;
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long long dp[70010];
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int main(){
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cin >> n >> k;
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for(int i = 1; i <= n; i++){
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dp[i] = dp[i-1] + i;
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}
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for(int i = k; i <= n; i++){
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long long curr = dp[i] - dp[i-k];
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// 判断这个数是不是某一个数的平方
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if((int)sqrt(curr) * (int)sqrt(curr) == curr){
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cnt++;
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}
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}
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cout << cnt;
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return 0;
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}
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