代码随想录二刷day45

提示：文章写完后，目录可以自动生成，如何生成可参考右边的帮助文档

---

前言

---

一、力扣70. 爬楼梯

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

二、力扣322. 零钱兑换

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

三、力扣279. 完全平方数

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