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)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static readonly int INFTY = int.MaxValue;
        static int[] segment;
        static int size;

        static void Main(string[] args)
        {
            string[] input1 = Console.ReadLine().Split(' ');
            int n = int.Parse(input1[0]);
            int q = int.Parse(input1[1]);

            Init(n);

            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < q; i++)
            {
                string[] input2 = Console.ReadLine().Split(' ');
                int c = int.Parse(input2[0]);
                int x = int.Parse(input2[1]);
                int y = int.Parse(input2[2]);

                if (c == 0) Update(x, y);
                else
                {
                    sb.AppendLine(Query(x, y + 1, 0, 0, size).ToString());
                }
            }
            Console.Write(sb);
        }

        static void Init(int n)
        {
            size = 1;

            while (size < n) size *= 2;

            segment = Enumerable.Repeat(INFTY, 2 * size - 1).ToArray();
        }

        static void Update(int i, int a)
        {
            i += size - 1;
            segment[i] = a;

            while (i > 0)
            {
                i = (i - 1) / 2;
                segment[i] = Math.Min(segment[i * 2 + 1], segment[i * 2 + 2]);
            }
        }

        static int Query(int a, int b, int k, int l, int r)
        {
            if (r <= a || b <= l) return INFTY;

            if (a <= l && r <= b) return segment[k];
            else
            {
                int vl = Query(a, b, k * 2 + 1, l, (l + r) / 2);
                int vr = Query(a, b, k * 2 + 2, (l + r) / 2, r);

                return Math.Min(vl, vr);
            }
        }
    }
}