NC_91_LONGEST_INCRE_SUBARRY NC_92_LCSII NC_93_LRU
package org.example.interview.practice; import java.util.Arrays; /** * @author xianzhe.ma * @date 2021/7/24 */ public class NC_91_LONGEST_INCRE_SUBARRY { public static int[] LIS (int[] arr) { // write code here int[] dp = new int[arr.length]; int[] subset = new int[arr.length + 1]; int len = 0; for (int i = 0; i < arr.length; i++) { if (subset[len] < arr[i]) { len += 1; subset[len] = arr[i]; dp[i] = len; } else { int idx = Arrays.binarySearch(subset, 0, len, arr[i]); if (idx < 0) { idx = -(idx + 1); } subset[idx] = arr[i]; dp[i] = idx; } } int[] res = new int[len]; for (int i = arr.length - 1; i >= 0; i--) { if (dp[i] == len) { res[--len] = arr[i]; } } return res; } public static void printArr(int[] arr) { for (int i=0;i<arr.length;i++) { System.out.print(arr[i] + " "); } } public static int[] LIS2 (int[] arr) { int length = arr.length; int[] subSet = new int[length + 1]; int[] dp = new int[length]; int len = 0; for (int i= 0;i < length; i++) { if (subSet[len] < arr[i]) { len ++; subSet[len] = arr[i]; dp[i] = len; } else { int index = Arrays.binarySearch(subSet, 0,len, arr[i]); if (index < 0) { index = -(index + 1); } subSet[index] = arr[i]; dp[i] = index;//index就是长度,因为subSet下标0永远是0 } } int[] res = new int[len]; for (int i = arr.length - 1; i >= 0; i--) { if (dp[i] == len) { res[--len] = arr[i]; } } return res; } public static void main (String[] args) { // int[] arr = {1,2,3,4,5,6,7}; // int index = Arrays.binarySearch(arr, 0, arr.length, 1); // System.out.println(index); int[] arr = {2,1,5,3,6,4,8,9,7}; printArr(LIS2(arr)); // int[] arr2 = {1,1,2,3,4}; // int index = Arrays.binarySearch(arr2, 0, 5, 1); // System.out.println(index); } }
package org.example.interview.practice; /** * @author xianzhe.ma * @date 2021/7/15 */ public class NC_92_LCSII { public static String LCS (String s1, String s2) { // write code here int len1 = s1.length(); int len2 = s2.length(); if(len1 == 0 || len2 == 0) return "-1"; int[][] dp = new int[len1+1][len2+1]; for(int i = 0; i < len1+1; i++){ for(int j = 0; j < len2+1; j++){ //初始化行列第一个元素 if(i == 0 || j == 0){ dp[i][j] = 0; continue; } if(s1.charAt(i-1) == s2.charAt(j-1)){ dp[i][j] = dp[i-1][j-1]+1; }else{ dp[i][j] = Math.max(dp[i-1][j], dp[i][j-1]); } } } //找出一个最长的公共子序列 StringBuilder sb = new StringBuilder(); int s1L = len1, s2L = len2; while(s1L != 0 && s2L != 0){ if (s1.charAt(s1L-1) == s2.charAt(s2L-1)){ sb.append(s1.charAt(s1L - 1)); s1L--; s2L--; }else{ if (dp[s1L-1][s2L] > dp[s1L][s2L-1]){ s1L--; }else{ s2L--; } } } if(sb.length() == 0) return "-1"; return sb.reverse().toString(); } public static String LCSii (String s1, String s2) { // write code here int len1 = s1.length(); int len2 = s2.length(); if(len1 == 0 || len2 == 0) return "-1"; int[][] dp = new int[len1+1][len2+1]; for(int i = 0; i < len1+1; i++){ for(int j = 0; j < len2+1; j++){ //初始化行列第一个元素 if(i == 0 || j == 0){ dp[i][j] = 0; continue; } if(s1.charAt(i-1) == s2.charAt(j-1)){ dp[i][j] = dp[i-1][j-1]+1; }else{ dp[i][j] = Math.max(dp[i-1][j], dp[i][j-1]); } } } //找出一个最长的公共子序列 StringBuilder sb = new StringBuilder(); int s1L = len1, s2L = len2; while(s1L != 0 && s2L != 0){ if (s1.charAt(s1L-1) == s2.charAt(s2L-1)){ sb.append(s1.charAt(s1L - 1)); s1L--; s2L--; }else{ if (dp[s1L-1][s2L] > dp[s1L][s2L-1]){ s1L--; }else{ s2L--; } } } if(sb.length() == 0) return "-1"; return sb.reverse().toString(); } public static void main (String[] args) { String s1 = "1A2C3D4B56"; String s2 = "B1D23A456A"; System.out.println(LCS (s1, s2)); } }
package org.example.interview.practice; import java.util.ArrayList; import java.util.LinkedHashMap; import java.util.Map; /** * @author xianzhe.ma * @date 2021/11/9 */ public class NC_93_LRU { public int[] LRU (int[][] operators, int k) { // write code here ArrayList<Integer> res = new ArrayList<>(); LinkedHashMap<Integer, Integer> lru = new LinkedHashMap<Integer, Integer>() { @Override protected boolean removeEldestEntry(Map.Entry<Integer, Integer> eldest) { return size() > k; // 大于限定的 lru 大小时删除最老的元素 } }; for (int[] e : operators) { if (e[0] == 1) { lru.put(e[1], e[2]); } else { int value = -1; if (lru.containsKey(e[1])) { value = lru.remove(e[1]); // 删除 lru.put(e[1], value); // 重新插入,成为最新的元素 } res.add(value); } } return res.stream().mapToInt(Integer::valueOf).toArray(); // 转换为数组 } }