Problem:
Range Minimum Query (RMQ)

Write a program which manipulates a sequence A = {a0, a1, . . . , an-1} with the following operations:

find(s, t): report the minimum element in as, as+1, . . . ,at.

update(i, x): change ai to x.

Note that the initial values of ai (i = 0, 1, . . . , n−1) are 231-1.

Input

n q
com0 x0 y0
com1 x1 y1
...
comq−1 xq−1 yq−1

In the first line, n (the number of elements in A) and q (the number of queries) are given. Then, q queries are given where com represents the type of queries. '0' denotes update(xi, yi) and '1' denotes find(xi, yi).

Output

For each find operation, print the minimum element.

Constraints

1 ≤ n ≤ 100000

1 ≤ q ≤ 100000

If comi is 0, then 0 ≤ xi < n, 0 ≤ yi < 231-1.

If comi is 1, then 0 ≤ xi < n, 0 ≤ yi < n.

Sample Input 1

3 5
0 0 1
0 1 2
0 2 3
1 0 2
1 1 2

Sample Output 1

1
2

Sample Input 2

1 3
1 0 0
0 0 5
1 0 0

Sample Output 2

2147483647
5

Solution in C (judge verdict: Accepted)

#include<stdio.h>
int MIN(int a,int b){return a<b?a:b;}
int M=2147483647;
int a[400010];
int f(int x,int y,int i,int l,int r){
  if(r<=x||y<=l)return M;
  if(x<=l&&r<=y)return a[i];
  return MIN(f(x,y,i*2,l,(l+r)/2),f(x,y,i*2+1,(l+r)/2,r));
}  
int main(){
  int n,t,q,x,y,i,m;
  scanf("%d %d",&n,&m);
  for(t=1;t<n;t*=2);
  for(i=1;i<t*2;i++)a[i]=M;
  while(m--){
    scanf("%d %d %d",&q,&x,&y);
    if(q)printf("%d\n",f(x,y+1,1,0,t));
    else{
      x+=t;
      for(a[x]=y;x-1;x/=2)a[x/2]=MIN(a[x],a[x^1]);
    }
  }
  return 0;
}