LOJ#515. 「LibreOJ β Round #2」贪心只能过样例(bitset)

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#include<iostream>
#include<cstring>
#include<cstdio>
#include<algorithm>
#include<bitset>
#define rg register
using namespace std;
const int MAXN = 1e6 + 10001, mod = 19650827;
inline int read() {
    char c = getchar();int x = 0,f = 1;
    while(c < '0' || c > '9'){if(c == '-')f = -1;c = getchar();}
    while(c >= '0' && c <= '9'){x = x * 10 + c - '0',c = getchar();}
    return x * f;
}
int N;
bitset<MAXN> pre, nxt;
int main() {
    N = read();N--;
    int l = read(), r = read();
    for(rg int i = l; i <= r; i++) pre[i * i] = 1;
    for(rg int i = 1; i <= N; i++) {
        int l = read(), r = read();
        nxt.reset();
        for(rg int k = l; k <= r; k++) 
            nxt |= pre << (k * k);
        pre = nxt;
    }
    printf("%d", nxt.count());
    return 0;
}