hdu 5317 RGCDQ

题目链接：hdu 5317 RGCDQ

#include <cstdio>#include <cstring>#include <cmath>#include <algorithm>using namespace std;const int maxn = 1e6;int F[maxn + 5], C[maxn + 5][10];void init () {memset(F, 0, sizeof(F));for (int i = 2; i <= maxn; i++) {if (F[i]) continue;for (int j = i; j <= maxn; j += i)F[j]++;}memset(C[1], 0, sizeof(C[1]));for (int i = 2; i <= maxn; i++) {memcpy(C[i], C[i-1], sizeof(C[i]));C[i][F[i]]++;}}int main () {init();int t, l, r, c[10];scanf("%d", &t);for (int i = 0; i < t; i++) {scanf("%d%d", &l, &r);int ans = 1;for (int j = 2; j <= 7; j++) {c[j] = C[r][j] - C[l-1][j];if (c[j] >= 2)ans = max(ans, j);}if (c[3] + c[6] >= 2)ans = max(ans, 3);if (c[2] + c[4] + c[6] >= 2)ans = max(ans, 2);printf("%d\n", ans);}return 0;}