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.IO;

namespace DSL2_A
{
    class RMQ
    {
        internal int n;
        internal int[] dat;

        public RMQ(int t)
        {
            n = t;
            dat = new int[2 * n - 1];
            for (int i = 0; i < 2 * n - 1; i++)
            {
                dat[i] = int.MaxValue;
            }
        }

        public void update(int k, int a)
        {
            k += n - 1;
            dat[k] = a;
            while (k > 0)
            {
                k = (k - 1) / 2;
                dat[k] = Math.Min(dat[k * 2 + 1], dat[k * 2 + 2]);
            }  
        }

        public int query(int a, int b, int k, int l, int r)
        {
            if (r <= a || b <= l) return int.MaxValue;

            if (a <= l && r <= b) return dat[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);
            }
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
            Console.SetOut(sw);
            var t = scan;
            int n_ = t[0];
            int q = t[1];

            int n = 1;
            while (n < n_) n *= 2;

            var ST = new RMQ(n);
            for (int i = 0; i < q; i++)
            {
                t = scan;
                if (t[0] == 0)
                {
                    ST.update(t[1], t[2]);
                }
                else if(t[0] == 1)
                {
                    Console.WriteLine(ST.query(t[1], t[2] + 1, 0, 0, n));
                }
            }
            Console.Out.Flush();
        }

        static int[] scan { get { return Array.ConvertAll(Console.ReadLine().Split(), int.Parse); } }
    }

}