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1 HDU 6069 Counting Divisors

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <algorithm>
#include <queue>
#include <vector>
#include <stack>
#include <map>
#include <set>
#include <cmath>
#include <cctype>
#include <ctime>

using namespace std;

#define REP(i, n) for (int i = 0; i < (n); ++i)
#define eps 1e-9

typedef long long ll;
typedef pair<int, int> pii;

const int INF = 0x7fffffff;
const int maxn = 1.1e6;
const ll mod = 998244353;
int T, k, prime_cnt = 0, cnt;
ll l, r, ans;
int prime[maxn];
bool vis[maxn];
ll ans_t[maxn], a[maxn];

void init() {
    for (int i = 2; i < maxn; ++i) {
        if (!vis[i]) {
            prime[prime_cnt++] = i;
            for (int j = i; j < maxn; j += i) { vis[j] = true; }
        }
    }
}
void cal(int x) {
    ll l_t, t; t = l / prime[x];
    if (t * prime[x] == l) { l_t = l; } else { l_t = (t + 1) * prime[x]; }
    if (l_t > r) { return; }
//    printf("prime = %d, l_t = %I64d
", prime[x], l_t);
    for (ll i = l_t - l; i <= r - l; i += prime[x]) {
        cnt = 1; a[i] /= prime[x];
        while (a[i] % prime[x] == 0) { a[i] /= prime[x]; ++cnt; }
        ans_t[i] *= 1ll * cnt * k + 1; ans_t[i] %= mod;
    }
}

int main() {
#ifdef __AiR_H
    freopen("in.txt", "r", stdin);
//    freopen("out.txt", "w", stdout);
#endif // __AiR_H
    scanf("%d", &T); init();
    while (T--) {
        scanf("%I64d %I64d %d", &l, &r, &k); ans = 0;
        for (ll i = 0; i <= r - l; ++i) { a[i] = l + i; ans_t[i] = 1; }
        for (int i = 0; i < prime_cnt; ++i) { cal(i); }
        for (ll i = 0; i <= r - l; ++i) {
            if (a[i] != 1) { ans_t[i] *= k + 1; ans_t[i] %= mod; }
        }
//        for (int i = 0; i <= r - l; ++i) {
//            printf("i = %d %I64d
", i, ans_t[i]);
//        }
//        printf("
");
        for (int i = 0; i <= r - l; ++i) { ans = (ans + ans_t[i]) % mod; }
        printf("%I64d
", ans);
    }
#ifdef __AiR_H
    printf("Time used = %.2fs
", (double)clock() / CLOCKS_PER_SEC);
#endif // __AiR_H
    return 0;
}