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>
#include <limits.h>
#include <math.h>

#define N (1 << 20)

int seg[N << 1];
void init(void)
{
	int i;
	for (i = 0; i < (N << 1); i++){
		seg[i] = INT_MAX;
	}
}
int find(int a, int b, int x, int l, int r)
{
	if (a >= r || l >= b) return (INT_MAX);
	if (a <= l && r <= b) return (seg[x]);
	return (fmin(find(a, b, x + x + 1, l, l + r >> 1), find(a, b, x + x + 2, l + r >> 1, r)));
}
void update(int x, int v)
{
	seg[x += N - 1] = v;
	while (x){
		x = x - 1 >> 1;
		seg[x] = fmin(seg[x + x + 1], seg[x + x + 2]);
	}
}

int main(void)
{
	int n, q;

	init();
	scanf("%d %d", &n, &q);
	while (q--){
		int qid, pos, val;
		scanf("%d %d %d", &qid, &pos, &val);
		if (qid) printf("%d\n", find(pos, val + 1, 0, 0, N));
		else update(pos, val);
	}
	return (0);
}