A Simple Problem with Integers~POJ - 3468
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
Hint
The sums may exceed the range of 32-bit integers
这题也是线段树的模板题我上一篇写的是单点更新 这一篇为区间更新 。
这题很适合线段树入门。
1 #include<cstdio> 2 #include<cstring> 3 #include<algorithm> 4 #include<queue> 5 using namespace std; 6 #define maxn 100005 7 long long sum[maxn<<2],add[maxn<<2]; 8 void pushup(int rt) { 9 sum[rt]=sum[rt<<1]+sum[rt<<1|1]; 10 } 11 void pushdown(int rt ,int l) { 12 if (add[rt]) { 13 add[rt<<1]+=add[rt]; 14 add[rt<<1|1]+=add[rt]; 15 sum[rt<<1]+=add[rt]*(l-(l>>1)); 16 sum[rt<<1|1]+=add[rt]*(l>>1); 17 add[rt]=0; 18 } 19 } 20 void build(int l,int r,int rt) { 21 if (l==r) { 22 scanf("%lld",&sum[rt]); 23 return ; 24 } 25 int m=(l+r)>>1; 26 build(l,m,rt<<1); 27 build(m+1,r,rt<<1|1); 28 pushup(rt); 29 } 30 void updata(int x,int y,int z,int l,int r,int rt) { 31 if (x<=l && r<=y) { 32 add[rt]+=z; 33 sum[rt]+=(long long)z*(r-l+1); 34 return ; 35 } 36 pushdown(rt,r-l+1); 37 int m=(l+r)>>1; 38 if (x<=m) updata(x,y,z,l,m,rt<<1); 39 if (y>m) updata(x,y,z,m+1,r,rt<<1|1); 40 pushup(rt); 41 } 42 long long query(int x,int y,int l,int r,int rt) { 43 long long ans=0; 44 if (x<=l && r<=y ) return sum[rt]; 45 pushdown(rt,r-l+1); 46 int m=(l+r)>>1; 47 if (x<=m) ans+=query(x,y,l,m,rt<<1); 48 if (y>m ) ans+=query(x,y,m+1,r,rt<<1|1); 49 return ans; 50 } 51 int main() { 52 int n,q; 53 while(scanf("%d%d",&n,&q)!=EOF) { 54 build(1,n,1); 55 char b[2]; 56 int x,y,z; 57 while(q--) { 58 scanf("%s",b); 59 if (b[0]=='Q') { 60 scanf("%d%d",&x,&y); 61 printf("%lld\n",query(x,y,1,n,1)); 62 } else { 63 scanf("%d%d%d",&x,&y,&z); 64 updata(x,y,z,1,n,1); 65 } 66 } 67 } 68 return 0; 69 }
