“玲珑杯”ACM比赛 Round #5 H -- Variance 简单树状数组

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <algorithm>
#define IOS ios::sync_with_stdio(false)
using namespace std;
#define inf (0x3f3f3f3f)
typedef long long int LL;
#define MY "H:/CodeBlocks/project/CompareTwoFile/DataMy.txt", "w", stdout
#define ANS "H:/CodeBlocks/project/CompareTwoFile/DataAns.txt", "w", stdout

#include <iostream>
#include <sstream>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <string>
const int maxn = 1e6 + 20;
int n, m;
LL c_pow[maxn];
LL c[maxn];
LL a[maxn];
int lowbit(int x) {
return x & (-x);
}
void upDate_pow(int pos, LL val) {
while (pos <= n) {
c_pow[pos] += val;
pos += lowbit(pos);
}
}
void upDate(int pos, LL val) {
while (pos <= n) {
c[pos] += val;
pos += lowbit(pos);
}
}
LL query_pow(int pos) {
LL ans = 0;
while (pos > 0) {
ans += c_pow[pos];
pos -= lowbit(pos);
}
return ans;
}
LL query(int pos) {
LL ans = 0;
//    if (pos < 0) arrest
while (pos > 0) {
ans += c[pos];
pos -= lowbit(pos);
}
return ans;
}
void work() {
scanf("%d%d", &n, &m);
for (int i = 1; i <= n; ++i) {
scanf("%lld", &a[i]);
upDate(i, a[i]);
upDate_pow(i, a[i] * a[i]);
}
bool flag1 = false;
for (int i = 1; i <= m; ++i) {
int flag;
scanf("%d", &flag);
if (flag == 1) {
int x, y;
scanf("%d%d", &x, &y);
LL now = query(x) - query(x - 1);
upDate(x, -now);
upDate(x, y);

now = query_pow(x) - query_pow(x - 1);
upDate_pow(x, -now);
upDate_pow(x, y * y);
} else {
int L, R;
scanf("%d%d", &L, &R);
LL t1 = (query_pow(R) - query_pow(L - 1)) * (R - L + 1);
LL haha = query(R) - query(L - 1);
LL t2 = -2 * haha * haha;
LL t3 = t2 / -2;
printf("%lld\n", t1 + t2 + t3);
}
}
}
int main() {
#ifdef local
freopen("data.txt","r",stdin);
#endif
work();
return 0;
}