CODE 62. Climbing Stairs

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You are climbing a stair case. It takes n steps to reach to the top.
Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

public int climbStairs(int n) {
	// Note: The Solution object is instantiated only once and is reused by
	// each test case.
	if (n <= 0) {
		return 0;
	} else if (1 == n) {
		return 1;
	} else if (2 == n) {
		return 2;
	}
	int[] ways = new int[n + 1];
	ways[1] = 1;
	ways[2] = 2;
	for (int i = 3; i <= n; i++) {
		ways[i] = ways[i - 1] + ways[i - 2];
	}
	return ways[n];
}