[SDOI2014]数表
[SDOI2014]数表
https://ac.nowcoder.com/acm/problem/20367
[SDOI2014]数表
/* Author : lifehappy */ #include <bits/stdc++.h> using namespace std; typedef long long ll; const int N = 1e5 + 10; int prime[N], mu[N], ans[N], tree[N], cnt; bool st[N]; struct Node { int id, sigma; bool operator < (const Node &T) const { return sigma < T.sigma; } }a[N]; struct Ask { int n, m, a, id; bool operator < (const Ask &T) const { return a < T.a; } }ask[N]; void init() { mu[1] = 1; for(int i = 2; i < N; i++) { if(!st[i]) { prime[++cnt] = i; mu[i] = -1; } for(int j = 1; j <= cnt && 1ll * i * prime[j] < N; j++) { st[i * prime[j]] = 1; if(i % prime[j] == 0) { break; } mu[i * prime[j]] = -mu[i]; } } for(int i = 1; i < N; i++) { a[i].id = i; for(int j = i; j < N; j += i) { a[j].sigma += i; } } } int lowbit(int x) { return (-x) & x; } void update(int x, int value) { while(x < N) { tree[x] += value; x += lowbit(x); } } int query(int x) { int ans = 0; while(x) { ans += tree[x]; x -= lowbit(x); } return ans; } int calc(int n, int m) { if(n > m) swap(n, m); int ans = 0; for(int l = 1, r; l <= n; l = r + 1) { r = min(n / (n / l), m / (m / l)); ans = ans + (n / l) * (m / l) * (query(r) - query(l - 1)); } return ans; } int main() { // freopen("in.txt", "r", stdin); // freopen("out.txt", "w", stdout); // ios::sync_with_stdio(false), cin.tie(0), cout.tie(0); init(); int Q; scanf("%d", &Q); for(int i = 1; i <= Q; i++) { scanf("%d %d %d", &ask[i].n, &ask[i].m, &ask[i].a); ask[i].id = i; } sort(ask + 1, ask + 1 + Q); sort(a + 1, a + N); int pos = 1; for(int i = 1; i <= Q; i++) { while(pos < N && a[pos].sigma <= ask[i].a) { for(int j = a[pos].id; j < N; j += a[pos].id) { update(j, a[pos].sigma * mu[j / a[pos].id]); } pos++; } ans[ask[i].id] = calc(ask[i].n, ask[i].m); } for(int i = 1; i <= Q; i++) { printf("%d\n", ans[i] & ((1ll << 31) - 1)); } return 0; }