Description
You have N integers, A1, A2, ... , AN. You need to deal with two kinds of operations. One type of operation is to add some given number to each number in a given interval. The other is to ask for the sum of numbers in a given interval.
Input
The first line contains two numbers N and Q. 1 ≤ N,Q ≤ 100000.
The second line contains N numbers, the initial values of A1, A2, ... , AN. -1000000000 ≤ Ai ≤ 1000000000.
Each of the next Q lines represents an operation.
"C a b c" means adding c to each of Aa, Aa+1, ... , Ab. -10000 ≤ c ≤ 10000.
"Q a b" means querying the sum of Aa, Aa+1, ... , Ab.
Output
You need to answer all Q commands in order. One answer in a line.
Sample Input
10 5
1 2 3 4 5 6 7 8 9 10
Q 4 4
Q 1 10
Q 2 4
C 3 6 3
Q 2 4
Sample Output
4
55
9
15
一道线段树的模板题,把模板敲一遍就ok。
#include <iostream>
#include <cstring>
using namespace std;
const int MAXN = 100010;
typedef long long ll;
ll a[MAXN], ans[MAXN<<2], lazy[MAXN<<2];
//a[]原序列信息,ans[]模拟线段树维护区间和,lazy[]懒得标记
void PushUp(int rt) {
ans[rt] = ans[rt<<1] + ans[rt<<1|1];
}
void Build(int l, int r, int rt) {
if(l == r) {
ans[rt] = a[l];
return;
}
int mid = (l + r) >> 1;
Build(l, mid, rt<<1);
Build(mid + 1, r, rt<<1|1);
PushUp(rt);
}
void PushDown(int rt, int ln, int rn) {
if(lazy[rt]) {
lazy[rt<<1] += lazy[rt];
lazy[rt<<1|1] += lazy[rt];
ans[rt<<1] += lazy[rt]*ln;
ans[rt<<1|1] += lazy[rt]*rn;
lazy[rt] = 0;
}
}
void Add(int L, int c, int l, int r, int rt) {//点更新
if(l == r) {
ans[rt] += c;
return;
}
int mid = (l + r) >> 1;
if(L <= mid) {
Add(L, c, l, mid, rt<<1);
} else {
Add(L, c, mid + 1, r, rt<<1|1);
}
PushUp(rt);
}
void Update(int L, int R, int C, int l, int r, int rt) {//区间更新
if( L <= l && r <= R) {
ans[rt] += C*(r - l + 1);
lazy[rt] += C;
return;
}
int mid = (l + r) >> 1;
PushDown(rt, mid - l + 1, r - mid);
if(L <= mid) {
Update(L, R, C, l, mid, rt<<1);
}
if(R > mid) {
Update(L, R, C, mid + 1, r, rt<<1|1);
}
PushUp(rt);
}
ll Query(int L, int R, int l, int r, int rt) {//区间查询
if(L <= l && r <= R) {
return ans[rt];
}
int mid = (l + r) >> 1;
PushDown(rt, mid - l + 1, r - mid);
ll ANS = 0;
if(L <= mid) {
ANS += Query(L, R, l, mid, rt<<1);
}
if(R > mid) {
ANS += Query(L, R, mid + 1, r, rt<<1|1);
}
return ANS;
}
int main() {
int n, m, x, y, c;
char ch;
while(cin>>n>>m) {
memset(a, 0, sizeof(a));
for(int i = 1; i <= n; i++) {
cin>>a[i];
}
Build(1, n, 1);
while(m--) {
getchar();
cin>>ch;
if(ch == 'Q') {
cin>>x>>y;
cout<<Query(x, y, 1, n, 1)<<endl;
} else {
cin>>x>>y>>c;
Update(x, y, c, 1, n, 1);
}
}
}
return 0;
}