leetCode : DP

src/main/java/sgyj/inflearn/yeji/section9/Solution5.java

@@ -0,0 +1,36 @@
+package sgyj.inflearn.yeji.section9;
+
+import java.awt.print.Pageable;
+import java.util.Arrays;
+import java.util.Scanner;
+
+// 동전교환
+public class Solution5 {
+    private static int n, m;
+    private static int[] dy;
+
+    private static int solution(int n, int[] coins, int result){
+        Arrays.fill( dy,Integer.MAX_VALUE );
+        dy[0] = 0;
+        for(int i=0; i<n; i++){
+            for(int j=coins[i]; j<=m; j++){
+                dy[j]=Math.min( dy[j],dy[j-coins[i]]+1 );
+            }
+        }
+
+        return dy[m];
+    }
+
+    public static void main ( String[] args ) {
+        Scanner sc = new Scanner( System.in );
+        int n = sc.nextInt();
+        int[] arr = new int[n];
+        for(int i=0; i<n; i++){
+            arr[i] = sc.nextInt();
+        }
+        m = sc.nextInt();
+        dy = new int[m+1];
+        System.out.println(solution( n,arr,m ));
+    }
+
+}

src/main/java/sgyj/leetcode/Readme.md

@@ -26,4 +26,12 @@
 
 - [200. Number of Islands](https://leetcode.com/problems/number-of-islands/description/)
 - [1091. Shortest Path in Binary Matrix](https://leetcode.com/problems/shortest-path-in-binary-matrix/)
-- [841. Keys and Rooms](https://leetcode.com/problems/keys-and-rooms/description/)
+- [841. Keys and Rooms](https://leetcode.com/problems/keys-and-rooms/description/)
+
+## DP
+
+- [746. Min Cost Climbing Stairs](https://leetcode.com/problems/min-cost-climbing-stairs/description/)
+- [128. Longest Consecutive Sequence](https://leetcode.com/problems/longest-consecutive-sequence/)
+- [322. Coin Change](https://leetcode.com/problems/coin-change/description/)
+- [62. Unique Paths](https://leetcode.com/problems/unique-paths/description/)
+- [198. House Robber](https://leetcode.com/problems/house-robber/description/)

src/main/java/sgyj/leetcode/yeji/section6/Solution198.java

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+package sgyj.leetcode.yeji.section6;
+
+// House Robber
+public class Solution198 {
+    private static int[] stillMoney;
+
+    public static int rob(int[] nums) {
+        int answer = 0;
+        stillMoney = new int[nums.length];
+        for(int n=0; n<nums.length; n++){
+            stillMoney[n] = nums[n];
+        }
+
+        for(int n=2; n<nums.length; n++){
+            int max = 0;
+            for(int i=n-2; i>=0; i--){
+                max= Math.max(max,stillMoney[i]);
+            }
+            stillMoney[n]+=max;
+        }
+
+        for(int money:stillMoney){
+            answer = Math.max(answer,money);
+        }
+
+
+        return answer;
+    }
+
+    public static void main ( String[] args ) {
+        int[] nums = {1,2,3,1};
+
+        System.out.println(rob(nums));
+    }
+
+}

src/main/java/sgyj/leetcode/yeji/section6/Solution322.java

@@ -0,0 +1,23 @@
+package sgyj.leetcode.yeji.section6;
+
+import java.util.Arrays;
+
+// coin change
+public class Solution322 {
+
+    public int coinChange(int[] coins, int amount) {
+        int[] result = new int[amount+1];
+        Arrays.fill( result, Integer.MAX_VALUE - 1);
+        result[0] = 0;
+
+        for(int coin : coins){
+            for(int n = coin; n<=amount; n++){
+                int tmp = result[n-coin] + 1;
+                if(result[n]>tmp) result[n] = tmp;
+            }
+        }
+
+        return result[result.length-1] == Integer.MAX_VALUE-1 ? -1 : result[result.length-1];
+    }
+
+}

src/main/java/sgyj/leetcode/yeji/section6/Solution62.java

@@ -0,0 +1,43 @@
+package sgyj.leetcode.yeji.section6;
+
+// 62. Unique Paths
+/*
+There is a robot on an m x n grid. The robot is initially located at the top-left corner (i.e., grid[0][0]).
+The robot tries to move to the bottom-right corner (i.e., grid[m - 1][n - 1]). The robot can only move either down or right at any point in time.
+Given the two integers m and n, return the number of possible unique paths that the robot can take to reach the bottom-right corner.
+The test cases are generated so that the answer will be less than or equal to 2 * 109.
+*/
+
+public class Solution62 {
+    private static int[][] visited;
+    private static int answer = 0;
+    public static int uniquePaths(int m, int n) {
+
+        visited = new int[m][n];
+        visited[0][0] = 1;
+
+        for(int i=0; i<m; i++){
+            for(int j=0; j<n; j++){
+                int dx = 0;
+                int dy = 0;
+                if(i-1>=0){
+                    dx = visited[i-1][j];
+                }
+                if(j-1>=0){
+                    dy = visited[i][j-1];
+                }
+                visited[i][j] = dx+dy == 0 ? 1 : dx+dy;
+            }
+        }
+
+        return visited[m-1][n-1];
+    }
+
+    public static void main ( String[] args ) {
+        int m = 3;
+        int n = 2;
+
+        System.out.println(uniquePaths(m,n));
+
+    }
+}

src/main/java/sgyj/leetcode/yeji/section6/Solution746.java

@@ -0,0 +1,26 @@
+package sgyj.leetcode.yeji.section6;
+
+public class Solution746 {
+
+    public static int minCostClimbingStairs(int[] cost) {
+        int[] minCost = new int[cost.length+1];
+        int answer = 0;
+
+        for(int i=0; i<cost.length; i++){
+            minCost[i] = cost[i];
+        }
+
+        for(int i=2; i<minCost.length; i++){
+            int target1 = minCost[i] + minCost[i-1];
+            int target2 = minCost[i] + minCost[i-2];
+            minCost[i] = Math.min(target1,target2);
+        }
+
+        return minCost[minCost.length-1];
+    }
+
+    public static void main ( String[] args ) {
+        int[] cost = {1,100,1,1,1,100,1,1,100,1};
+        System.out.println(minCostClimbingStairs( cost ));
+    }
+}