weekly contest 314

Author: ZLBer

README.md

@@ -4,7 +4,8 @@ Record leetcode contest and ideas every week, and encourage yourself to think mo
 
 leetcode url: <https://leetcode.cn/u/cctest/>
 
-* 🐑 [weekly contest 311](src/main/java/weekly/wk311.java)     排序 | 脑筋急转弯 | 前缀和 | 并查集
+* 🐼 [weekly contest 314](src/main/java/weekly/wk312.java)     数组 | 异或运算 | 贪心+栈 | DP
+* 🐑 [weekly contest 312](src/main/java/weekly/wk312.java)     排序 | 脑筋急转弯 | 前缀和 | 并查集
 * 🐑 [weekly contest 311](src/main/java/weekly/wk311.java)     规律 | 滑动窗口 | 层序遍历 | 字典树
 * 🐑 [weekly contest 310](src/main/java/weekly/wk310.java)     排序、hash表 | 贪心 | 贪心、差分数组 | 线段树+区间最大值
 * 🐼 [weekly contest 309](src/main/java/weekly/wk309.java)     数组 | DP/记忆化搜索 | 滑动窗口 | 双堆

src/main/java/weekly/wk314.java

@@ -0,0 +1,117 @@
+package weekly;
+
+import java.util.ArrayDeque;
+import java.util.Deque;
+import java.util.Map;
+
+public class wk314 {
+    //ranking: 610 / 4838
+
+    //简单题，遍历比较
+    public int hardestWorker(int n, int[][] logs) {
+        int pre = 0;
+        int ans = Integer.MAX_VALUE;
+        int time = 0;
+        for (int i = 0; i < logs.length; i++) {
+            if (logs[i][1] - pre > time || (logs[i][1] - pre == time && logs[i][0] < ans)) {
+                ans = logs[i][0];
+                time = logs[i][1] - pre;
+            }
+            pre = logs[i][1];
+        }
+        return ans;
+    }
+
+    //理解异或运算，a^a=0
+    public int[] findArray(int[] pref) {
+        int[] res = new int[pref.length];
+        for (int i = 0; i < pref.length; i++) {
+            res[i] = i==0?pref[i]:pref[i-1] ^ pref[i];
+        }
+        return res;
+    }
+
+    // 单调栈
+  /*  static public String robotWithString(String s) {
+        char[] chars = s.toCharArray();
+        Deque<Integer> deque = new ArrayDeque<>();
+        for (int i = 0; i < chars.length; i++) {
+            while (!deque.isEmpty() && chars[deque.peekLast()] > chars[i]) {
+                deque.pollLast();
+            }
+            deque.addLast(i);
+        }
+        Deque<Integer> d = new ArrayDeque<>();
+        StringBuilder sb = new StringBuilder();
+        for (int i = 0; i < chars.length; i++) {
+            if (!deque.isEmpty() && deque.peekFirst() == i) {
+                while (!d.isEmpty() && chars[d.peekLast()] <= chars[i]) {
+                    sb.append(chars[d.pollLast()]);
+                }
+                sb.append(chars[deque.pollFirst()]);
+                while (!deque.isEmpty() && !d.isEmpty() && chars[d.peekLast()] <= chars[deque.peekFirst()]) {
+                    sb.append(chars[d.pollLast()]);
+                }
+            } else if (!deque.isEmpty() && deque.peekFirst() > i) {
+                d.addLast(i);
+            }
+        }
+        while (!d.isEmpty()) {
+            sb.append(chars[d.pollLast()]);
+        }
+        return sb.toString();
+    }*/
+
+    //贪心写法
+   static public String robotWithString(String s) {
+        char[] chars = s.toCharArray();
+        char []mins=new char[s.length()+1];
+        mins[mins.length-1]='z';
+        for (int i = chars.length - 1; i >= 0; i--) {
+            if(mins[i+1]<chars[i]){
+                mins[i]=mins[i+1];
+            }else {
+                mins[i]=chars[i];
+            }
+        }
+        StringBuilder sb=new StringBuilder();
+        Deque<Character> deque=new ArrayDeque<>();
+        for (int i = 0; i < s.length(); i++) {
+            deque.addLast(chars[i]);
+            while (!deque.isEmpty()&&deque.peekLast()<=mins[i+1]){
+               sb.append(deque.pollLast());
+           }
+        }
+        while (!deque.isEmpty()){
+            sb.append(deque.pollLast());
+        }
+
+        return sb.toString();
+    }
+
+
+
+
+    //dp记录mod k的所有数目
+    public int numberOfPaths(int[][] grid, int k) {
+        int mod=(int)1e9+7;
+        int[][][] dp = new int[grid.length][grid[0].length][k];
+
+        dp[0][0][grid[0][0]%k]=1;
+
+        for (int i = 0; i < grid.length; i++) {
+            for (int j = 0; j <grid[0].length; j++) {
+                for (int kk = 0; kk < k; kk++) {
+                    if(i-1>=0)  dp[i][j][(kk+grid[i][j])%k]+=dp[i-1][j][kk];
+                    if(j-1>=0)  dp[i][j][(kk+grid[i][j])%k]+=dp[i][j-1][kk];
+                    dp[i][j][(kk+grid[i][j])%k]%=mod;
+                }
+            }
+        }
+        return dp[grid.length-1][grid[0].length-1][0];
+    }
+
+    public static void main(String[] args) {
+        robotWithString("bac");
+    }
+}