class Solution {public int climbStairs(int n) {int[] dp = new int[n+1];int m = 2;dp[0] = 1;for(int i = 1; i <= n; i++){for(int j = 1; j <= m; j++){if(i >= j)dp[i] += dp[i-j];}}return dp[n];}
}

class Solution {public int coinChange(int[] coins, int amount) {int[] dp = new int[amount+1];int max = Integer.MAX_VALUE;for(int j = 0; j < dp.length; j++){dp[j] = max;}dp[0] = 0;for(int i = 0; i < coins.length; i++){for(int j = coins[i]; j <= amount; j++){if(dp[j-coins[i]] != max){dp[j] = Math.min(dp[j], dp[j-coins[i]] + 1);}}}return dp[amount] == max ? -1:dp[amount];}
}

class Solution {public int numSquares(int n) {int[] dp = new int[n+1];int max = Integer.MAX_VALUE;for(int j = 0; j < dp.length; j++){dp[j] = max;}dp[0] = 0;for(int i = 1; i * i <= n; i++){for(int j = i * i; j <= n; j++){if(dp[j-i*i] != max){dp[j] = Math.min(dp[j], dp[j-i*i] + 1);}}}return dp[n];}
}