【BZOJ 2154】Crash的数字表格

制杖了，，，求前缀和的时候$i×i$是int，然后当$i=10^7$时就喜闻乐见地爆int了，，，对拍之后查了一个下午的错才发现这个问题，，，最后枚举用的变量全都强行加上long long才A掉

#include<cstdio>
#include<cstring>
#include<algorithm>
#define read(x) x=getint()
using namespace std;
typedef long long LL;
const int p = 20101009;
const int N = 1E7 + 3;
int getint() {
int k = 0, fh = 1; char c = getchar();
for(; c < '0' || c > '9'; c = getchar())
if (c == '-') fh = -1;
for(; c >= '0' && c <= '9'; c = getchar())
k = k * 10 + c - '0';
return k * fh;
}
bool np
;
int prime
, mu
, s
;
void shai(int n) {
mu[1] = 1; s[1] = 1; int num = 0;
for(int i = 2; i <= n; ++i) {
if (!np[i]) {
mu[i] = -1;
prime[++num] = i;
}
for(int j = 1; j <= num; ++j) {
int t = prime[j] * i;
if (t > n) break;
np[t] = 1;
if (i % prime[j] == 0) {mu[t] = 0; break;}
mu[t] = -mu[i];
}
s[i] = (s[i - 1] + (1LL * i * i * mu[i]) % p) % p;
}
}
LL sum(LL x, LL y) {return (((x * (x + 1) / 2) % p) * ((y * (y + 1) / 2) % p)) % p;}
LL F(LL x, LL y) {
LL re = 0;
for(int i = 1, la = 1; i <= x; i = la + 1) {
la = min(x / (x / i), y / (y / i));
re = (re + (s[la] - s[i - 1]) * sum(x / i, y / i) % p) % p;
}
return re;
}
int main() {
int n, m;
read(n); read(m);
if (n > m) swap(n, m);
shai(n);

LL ret = 0;
for(LL d = 1, la = 1; d <= n; d = la + 1) {
la = min(n / (n / d), m / (m / d));
ret = (ret + (d + la) * (la - d + 1) / 2 % p * F(n / d, m / d) % p) % p;
}
printf("%lld", (ret + p) % p);

return 0;
}

不知道该说些什么了......