modify code

Author: algorithmzuo

src/class47/Code01_StrangePrinter.java

@@ -3,7 +3,52 @@
 // 本题测试链接 : https://leetcode.com/problems/strange-printer/
 public class Code01_StrangePrinter {
 
-public static int strangePrinter(String s) {
+public static int strangePrinter1(String s) {
+if (s == null || s.length() == 0) {
+return 0;
+}
+char[] str = s.toCharArray();
+return process1(str, 0, str.length - 1);
+}
+
+public static int process1(char[] str, int L, int R) {
+if (L == R) {
+return 1;
+}
+int ans = R - L + 1;
+for (int k = L + 1; k <= R; k++) {
+ans = Math.min(ans, process1(str, L, k - 1) + process1(str, k, R) - (str[L] == str[k] ? 1 : 0));
+}
+return ans;
+}
+
+public static int strangePrinter2(String s) {
+if (s == null || s.length() == 0) {
+return 0;
+}
+char[] str = s.toCharArray();
+int N = str.length;
+int[][] dp = new int[N][N];
+return process2(str, 0, N - 1, dp);
+}
+
+public static int process2(char[] str, int L, int R, int[][] dp) {
+if (dp[L][R] != 0) {
+return dp[L][R];
+}
+int ans = R - L + 1;
+if (L == R) {
+ans = 1;
+} else {
+for (int k = L + 1; k <= R; k++) {
+ans = Math.min(ans, process2(str, L, k - 1, dp) + process2(str, k, R, dp) - (str[L] == str[k] ? 1 : 0));
+}
+}
+dp[L][R] = ans;
+return ans;
+}
+
+public static int strangePrinter3(String s) {
 if (s == null || s.length() == 0) {
 return 0;
 }

src/class47/Code03_DinicAlgorithm.java

@@ -0,0 +1,133 @@
+// 本题测试链接:
+// https://lightoj.com/problem/internet-bandwidth
+// 这是一道DinicAlgorithm算法的题
+// 把如下代码粘贴进网页所提供的编译器环境中
+// 选择java编译环境
+// 不需要修改任何内容可以直接通过
+// DinicAlgorithm用法请看网页上的题目描述并结合main函数的写法
+
+package class47;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.LinkedList;
+import java.util.Scanner;
+
+public class Code03_DinicAlgorithm {
+
+public static class Edge {
+public int from;
+public int to;
+public int available;
+
+public Edge(int a, int b, int c) {
+from = a;
+to = b;
+available = c;
+}
+}
+
+public static class Dinic {
+private int N;
+private ArrayList<ArrayList<Integer>> nexts;
+private ArrayList<Edge> edges;
+private int[] depth;
+private int[] cur;
+
+public Dinic(int nums) {
+N = nums + 1;
+nexts = new ArrayList<>();
+for (int i = 0; i <= N; i++) {
+nexts.add(new ArrayList<>());
+}
+edges = new ArrayList<>();
+depth = new int[N];
+cur = new int[N];
+}
+
+public void addEdge(int u, int v, int r) {
+int m = edges.size();
+edges.add(new Edge(u, v, r));
+nexts.get(u).add(m);
+edges.add(new Edge(v, u, 0));
+nexts.get(v).add(m + 1);
+}
+
+public int maxFlow(int s, int t) {
+int flow = 0;
+while (bfs(s, t)) {
+Arrays.fill(cur, 0);
+flow += dfs(s, t, Integer.MAX_VALUE);
+}
+return flow;
+}
+
+private boolean bfs(int s, int t) {
+depth[s] = 0;
+LinkedList<Integer> queue = new LinkedList<>();
+queue.addFirst(s);
+boolean[] visited = new boolean[N];
+visited[s] = true;
+while (!queue.isEmpty()) {
+int u = queue.pollLast();
+for (int i = 0; i < nexts.get(u).size(); i++) {
+Edge e = edges.get(nexts.get(u).get(i));
+int v = e.to;
+if (!visited[v] && e.available > 0) {
+visited[v] = true;
+depth[v] = depth[u] + 1;
+queue.addFirst(v);
+}
+}
+}
+return visited[t];
+}
+
+private int dfs(int s, int t, int r) {
+if (s == t || r == 0) {
+return r;
+}
+int f = 0;
+int flow = 0;
+for (; cur[s] < nexts.get(s).size(); cur[s]++) {
+int ei = nexts.get(s).get(cur[s]);
+Edge e = edges.get(ei);
+Edge o = edges.get(ei ^ 1);
+if (depth[e.to] == depth[s] + 1 && (f = dfs(e.to, t, Math.min(e.available, r))) != 0) {
+e.available -= f;
+o.available += f;
+flow += f;
+r -= f;
+if (r <= 0) {
+break;
+}
+}
+}
+return flow;
+}
+
+}
+
+public static void main(String[] args) {
+Scanner cin = new Scanner(System.in);
+int cases = cin.nextInt();
+for (int i = 1; i <= cases; i++) {
+int n = cin.nextInt();
+int s = cin.nextInt();
+int t = cin.nextInt();
+int m = cin.nextInt();
+Dinic dinic = new Dinic(n);
+for (int j = 0; j < m; j++) {
+int from = cin.nextInt();
+int to = cin.nextInt();
+int weight = cin.nextInt();
+dinic.addEdge(from, to, weight);
+dinic.addEdge(to, from, weight);
+}
+int ans = dinic.maxFlow(s, t);
+System.out.println("Case " + i + ": " + ans);
+}
+cin.close();
+}
+
+}