暑期训练狂刷系列——poj 3468 A Simple Problem with Integers （线段树+区间更新）

  1 #include <cstdio>
  2 #include <cstring>
  3 #include <iostream>
  4 #include <algorithm>
  5 using namespace std;
  6 const int maxn = 400010;
  7 const int INF = 0x3f3f3f3f;
  8 #define LL __int64
  9 struct node
 10 {
 11     LL L, R;
 12     LL sum, add;
 13     LL Mid()
 14     {
 15         return (L + R) / 2;
 16     }
 17 };
 18 node tree[maxn];
 19 LL res;
 20 
 21 void build(LL root, LL l, LL r)
 22 {
 23     tree[root].L = l;
 24     tree[root].R = r;
 25     tree[root].sum = tree[root].add = 0;
 26 
 27     if (l == r)
 28         return ;
 29     build (2*root+1, l, tree[root].Mid());
 30     build (2*root+2, tree[root].Mid()+1, r);
 31 }
 32 void insert (LL root, LL s, LL e, LL x)
 33 {
 34     tree[root].sum += x * (e - s + 1);
 35     if (tree[root].L == s && e == tree[root].R)//更新到区间
 36         {
 37             tree[root].add += x;
 38             return ;
 39         }
 40     if (e <= tree[root].Mid())
 41         insert (2*root+1, s, e, x);
 42     else if (tree[root].Mid() < s)
 43         insert (2*root+2, s, e, x);
 44     else
 45     {
 46         insert (2*root+1, s, tree[root].Mid(), x);
 47         insert (2*root+2, tree[root].Mid()+1, e, x);
 48     }
 49 }
 50 void query (LL root, LL s, LL e)
 51 {
 52 
 53     if (tree[root].L == s && e == tree[root].R)
 54     {
 55         res += tree[root].sum;
 56         return ;
 57     }
 58     if (tree[root].add)
 59     {//向下继续更新
 60         tree[2*root+1].add += tree[root].add;
 61         tree[2*root+2].add += tree[root].add;
 62         tree[2*root+1].sum += tree[root].add * (tree[2*root+1].R - tree[2*root+1].L + 1);
 63         tree[2*root+2].sum += tree[root].add * (tree[2*root+2].R - tree[2*root+2].L + 1);
 64         tree[root].add = 0;
 65     }
 66     if (e <= tree[root].Mid())
 67         query (2*root+1, s, e);
 68     else if (tree[root].Mid() < s)
 69         query (2*root+2, s, e);
 70     else
 71     {
 72         query (2*root+1, s, tree[root].Mid());
 73         query (2*root+2, tree[root].Mid()+1, e);
 74     }
 75 }
 76 int main ()
 77 {
 78     LL n, m, num;
 79     while (scanf ("%I64d %I64d", &n, &m) != EOF)
 80     {
 81         build (0, 1, n);
 82         for (int i=1; i<=n; i++)
 83         {
 84             scanf ("%I64d", &num);
 85             insert (0, i, i, num);
 86         }
 87         char str[2];
 88         LL s, e;
 89         while (m --)
 90         {
 91             scanf ("%s %I64d %I64d", str, &s, &e);
 92             if (str[0] == ‘Q‘)
 93             {
 94                 res = 0;
 95                 query (0, s, e);
 96                 printf ("%I64d\n", res);
 97             }
 98             else
 99             {
100                 scanf ("%I64d", &num);
101                 insert (0, s, e, num);
102             }
103         }
104     }
105     return 0;
106 }