HNU 12876 Quite Good Numbers 完美数变形

筛法是一种很快的方法，贴代码纪念一下。 做法很像筛法

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <string>
#include <queue>
#include <stack>
#include <vector>
#include <map>
#include <set>
#include <functional>
#include <time.h>

using namespace std;

const int INF = 1<<30;
const int MAXN = (int) 1e6+5;

int a[MAXN];

inline int myAbs(int x) {
    return x>0 ? x : -x;
}

int main() {
    #ifdef Phantom01
        freopen("HNU12876.in", "r", stdin);
    #endif //Phantom01

    memset(a, 0, sizeof(a));
    for (int i = 1; i < MAXN; i++)
        for (int j = i<<1; j < MAXN; j += i)
            a[j]+=i;
    for (int i = 1; i < MAXN; i++)
        a[i] = myAbs(a[i]-i);

    int l, r, k;
    int T = 1;
    while (scanf("%d%d%d", &l, &r, &k)!=EOF) {
        if (l==r&&r==k&&k==0) break;
        printf("Test %d: ", T++);
        int ans = 0;
        for (int i = l; i <= r; i++)
            if (a[i]<=k)
                ans++;
        printf("%d
", ans);
    }

    return 0;
}