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: WA: Presentation Error)

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

namespace AOJ2
{
    class Program
    {
        static void Main()
        {

            var nq = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();
            var array = Enumerable.Repeat(int.MaxValue, nq[0]).ToArray();
            var input = Read(nq[1]).ToArray();
            var result = new StringBuilder();
            string[] before = { "" };
            var beforeValue = 0;
            foreach (var com in input)
            {
                if (before.SequenceEqual(com))
                {
                    if (com[0] == "1")
                    {
                        result.AppendLine(beforeValue.ToString());
                    }
                    continue;
                }
                var x = int.Parse(com[1]);
                var y = int.Parse(com[2]);
                if (com[0] == "0")
                {
                    array[x] = y;
                }
                else
                {
                    int[] ary2 = new int[y - x + 1];
                    Buffer.BlockCopy(array, x*4, ary2,0, ary2.Length * 4);
                    beforeValue = ary2.Min();
                    result.AppendLine(beforeValue.ToString());

                }
                before = com;
            }
            Console.WriteLine(result.ToString());

        }

        private static IEnumerable<string[]> Read(int loop)
        {
            for (int i = 0; i < loop; i++)
            {
                yield return Console.ReadLine().Split(' ').ToArray();
            }
        }
    }
}