POJ 2777 Count Color(線段樹#1)

第一次瞭解到線段樹的lazy思想

422ms

#include <cstdio>
#include <cstring>
using namespace std;

#define N 100010



struct node{
       int l, r;
       int col;
       int lazy;//延遲標記 
}Tree[N * 4];
///

int L, T, O;

void build(int l, int r, int x)
{
     Tree[x].l = l;
     Tree[x].r = r;
     Tree[x].col = 0;
     Tree[x].lazy = 0; 
     if (l == r)return;
     int mid = (l + r) / 2;
     build(l, mid, x * 2);
     build(mid + 1, r, x * 2 + 1);
}


void push_down(int x)
{
      Tree[x * 2].col = Tree[x].col;
      Tree[x * 2 + 1].col = Tree[x].col;
      Tree[x].lazy = 0;
      Tree[x * 2].lazy = 1;
      Tree[x * 2 + 1].lazy = 1;
}

 
void update(int l, int r, int col, int x)
{
       if (Tree[x].l == l && r == Tree[x].r)
       {
                Tree[x].lazy = 1; 
                Tree[x].col = (1 << (col - 1));
                return; 
       }
       if (Tree[x].lazy)
             push_down(x); 
       int mid = (Tree[x].l + Tree[x].r) / 2;
       if (mid < l)update(l, r, col, x * 2 + 1);
       else if (mid >= r)update(l, r, col, x * 2);
       else {
            update(l, mid, col, x * 2);
            update(mid + 1, r, col, x * 2 + 1);
       }
       Tree[x].col = (Tree[x * 2].col | Tree[x * 2 + 1].col); 
} 


int find(int l, int r, int x)
{ 
       if ((Tree[x].l == l && r ==  Tree[x].r) || Tree[x].lazy)
       {
                return Tree[x].col; 
       }
       int mid = (Tree[x].l + Tree[x].r) / 2;
       if (mid < l)return find(l, r, x * 2 + 1);
       else if (mid >= r) return find(l, r, x * 2);
       else {
            return (find(l, mid,  x * 2) | find(mid + 1, r,  x * 2 + 1)) ; 
       } 
}      

int trans(int nu)
{
       int ans = 0;
       for (int i = 0; i < T; i++)
         if ((1 << i) & nu)ans++; 
        return ans;
}

 


int main()
{
    //FILE* fp = fopen("in.txt", "r"); 
    scanf( "%d %d %d", &L, &T, &O); 
    build(1, L, 1);
    Tree[1].lazy = 1;
    Tree[1].col = 1; 
    char op[3];
    int x, y, col;
    while (O--)
    {
          scanf( "%s %d %d", op, &x, &y);
          if (x > y)x ^= y, y ^= x, x ^= y; 
          if (op[0] == 'C')
          {
                 scanf( "%d", &col);
                 update(x, y, col, 1);
               //  for (int i = 1; i <= L ;i++)printf("%d ", color[i]);puts(""); 
          }
          else { 
               printf("%d\n", trans(find(x, y, 1)));
          }
    }
   // getchar();
    return 0;
}