POJ 3468 A Simple Problem with Integers(详细题解)

  1 #include<stdio.h>
  2 #include<iostream>
  3 #include<stack>
  4 #include<queue>
  5 #include<math.h>
  6 #include<stdlib.h>
  7 #include<cstring>
  8 using namespace std;
  9 
 10 #define max(a,b) (a>b?a:b)
 11 #define min(a,b) (a<b?a;b)
 12 #define INF 0xffffff0
 13 #define maxn 400010
 14 
 15 struct Node
 16 {
 17     int L, R;
 18     __int64 Sum, Inc;
 19     int Mid()
 20     {
 21         return (L+R)/2;
 22     }
 23 }Tree[maxn];//这里我们用数组保存线段树
 24 __int64  sum;
 25 void BulidTree(int root,int L,int R);
 26 void Insert(int root,int i,int v);
 27 void Add(int root,int s,int e,int v);
 28 void QuerySum(int root,int s,int e);
 29 
 30 int main()
 31 {
 32     int Q, N, v;
 33     scanf("%d%d",&N,&Q);
 34     BulidTree(0,1,N);
 35     for(int i = 1; i <= N; i++)
 36     {
 37         scanf("%d",&v);
 38         Insert(0,i,v);
 39     }
 40     int s, e;
 41     char str[2];
 42     while(Q--)
 43     {
 44         scanf("%s%d%d",str,&s,&e);
 45         if(str[0] == ‘Q‘)
 46         {
 47             sum = 0;
 48             QuerySum(0,s,e);
 49             printf("%I64d\n",sum);
 50         }
 51         else
 52         {
 53             scanf("%d",&v);
 54             Add(0,s,e,v);
 55         }
 56     }
 57     return 0;
 58 }
 59 
 60 void BulidTree(int root,int L,int R)
 61 {
 62     Tree[root].L = L;
 63     Tree[root].R = R;
 64     Tree[root].Inc = Tree[root].Sum = 0;
 65     if(L != R)
 66     {
 67         BulidTree(root*2+1,L,Tree[root].Mid());
 68         BulidTree(root*2+2,Tree[root].Mid()+1,R);
 69     }
 70 }
 71 void Insert(int root,int i,int v)
 72 {
 73     if(Tree[root].L == Tree[root].R)
 74     {
 75         Tree[root].Sum = v;
 76         return ;
 77     }
 78     Tree[root].Sum += v;
 79     if(i <= Tree[root].Mid())
 80         Insert(root*2+1,i,v);
 81     else
 82         Insert(root*2+2,i,v);
 83 }
 84 void Add(int root,int s,int e,int v)
 85 {
 86     if(Tree[root].L == s && Tree[root].R == e)
 87     {
 88         Tree[root].Inc += v;
 89         return ;
 90     }
 91     Tree[root].Sum += (e-s+1)*v;
 92     if(e <= Tree[root].Mid())
 93         Add(2*root+1,s,e,v);
 94     else if(s > Tree[root].Mid())
 95         Add(2*root+2,s,e,v);
 96     else
 97     {
 98         Add(root*2+1,s,Tree[root].Mid(),v);
 99         Add(root*2+2,Tree[root].Mid()+1,e,v);
100     }
101 }
102 void QuerySum(int root,int s,int e)
103 {
104     if(Tree[root].L == s && Tree[root].R == e)
105     {
106         sum += (Tree[root].R - Tree[root].L + 1)*Tree[root].Inc + Tree[root].Sum;
107         return ;
108     }
109     Tree[root].Sum += (Tree[root].R - Tree[root].L+1)*Tree[root].Inc;
110     if(Tree[root].Inc)
111     {
112         Tree[root*2+1].Inc += Tree[root].Inc;
113         Tree[root*2+2].Inc += Tree[root].Inc;
114     }
115     Tree[root].Inc = 0;
116     if(e <= Tree[root].Mid())
117         QuerySum(root*2+1,s,e);
118     else if(s > Tree[root].Mid())
119         QuerySum(root*2+2,s,e);
120     else
121     {
122         QuerySum(root*2+1,s,Tree[root].Mid());
123         QuerySum(root*2+2,Tree[root].Mid()+1,e);
124     }
125 }