Posted 2021-04-11 Warrior

01

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骞垮害浼樺厛

浠€涔堟槸骞垮害浼樺厛绠楁硶锛?/strong>

璁╂垜浠墦涓瘮鏂癸細姣斿浣犳槸涓€涓灉鍐滒煡紝

閭ｄ箞浣犲彲浠ョ户缁湪鏈嬪弸鐨勬湅鍙嬩腑瀵绘壘

鏈€鍚庣粓浜庡鎵惧埌浜嗚姃鏋滅粡閿€鍟嗐€?br>

鍏跺疄寰堢畝鍗曡繖绉嶇畻娉曢亶鍘嗕綘鐨勬暣涓汉闄呭叧绯荤綉锛岀洿鍒版壘鍒扮粡閿€鍟嗗氨鏄?span>骞垮害浼樺厛鎼滅储

骞垮害浼樺厛鎼滅储濡備笅鍥撅紝浼氬厛鍦ㄤ竴搴﹀叧绯绘壘锛岀劧鍚庢槸浜屽害鍏崇郴锛岃繖鏍峰眰灞傞€掕繘銆?/p>

骞垮害浼樺厛鎼滅储鍙互瑙ｅ喅涓ょ被闂

• 绗竴绫绘槸锛氫粠A鑺傜偣瑙﹀彂鏈夊墠寰€B鑺傜偣鐨勮矾寰勪箞锛堝湪浣犵殑鍏崇郴缃戜腑鏈夎姃鏋滅粡閿€鍟嗗悧锛夛紵

• 绗簩绫绘槸锛氫粠A鑺傜偣瑙﹀彂鍓嶅線B鑺傜偣鐨勫摢鏉¤矾寰勬渶鐭紙鍝釜鑺掓灉缁忛攢鍟嗕笌鎴戠殑鍏崇郴鏈€杩戯級

骞垮害浼樺厛鐨勪唬鐮佸疄鐜?/strong>

渚嬪瑕佸椤剁偣A杩涜骞垮害浼樺厛閬嶅巻锛屽鎵惧埌B鐨勬渶鐭矾寰?/p>

姝ラ濡備笅锛?/strong>

1. 棣栧厛闇€瑕佷竴涓槦鍒桻锛屾妸A鐨勪竴搴﹀ソ鍙嬫斁鍏ラ槦鍒椾腑

2. 鍐嶉渶瑕佷竴涓泦鍚圫锛岀敤浜庡瓨鏀惧凡缁忚闂繃鐨勫厓绱狅紝閬垮厤閫犳垚寰幆璁块棶鐨勬儏鍐?/p>

3. 瀵筈杩涜閬嶅巻锛岄槦棣栫殑鍏冪礌H涓嶅湪S涓紝骞朵笖涓嶆槸B锛屽垯閬嶅巻H鐨勪竴搴﹀ソ鍙嬫斁鍏ュ埌Q涓紝浠ユ寰幆閬嶅巻

浠ｇ爜瀹炵幇锛?br>

public class MyGraph {
 private LinkedList<Integer> adj[]; private int v; //椤剁偣鐨勪釜鏁?/span>
 public MyGraph(int v) { this.v = v; adj = new LinkedList[v]; for (int i = 0; i < v; i++) { adj[i] = new LinkedList<>(); } }
 public void addEdge(int s, int e) { adj[s].add(e); }
 public void bfs(int s,int t) { if(s == t) return; boolean[] visited = new boolean[v]; visited[s] = true; Queue<Integer> queue = new LinkedList<>(); queue.add(s); //鐢ㄤ簬璁板綍璋佽窡璋佺浉杩?/span> int[] prev = new int[v]; for (int i = 0; i < v; ++i) { prev[i] = -1; } while (queue.size()!=0){ Integer w = queue.poll(); for (int i = 0; i < adj[w].size(); i++) { int q = adj[w].get(i); if (!visited[q]){ prev[q] = w; if(q==t){ print(prev, s, t); return;  } visited[q] = true; queue.add(q); } } } } private void print(int[] prev, int s, int t) { // 閫掑綊鎵撳嵃s->t鐨勮矾寰?/span> if (prev[t] != -1 && t != s) { print(prev, s, prev[t]); } System.out.print(t + " "); }}

骞垮害浼樺厛绠楁硶鐨勬椂闂村鏉傚害姣旇緝濂界畻锛屽氨鏄偣鐨勪釜鏁板姞涓婅竟鐨勪釜鏁?/p>

O(V+E)锛岀敱浜庤竟鐨勪釜鏁颁細杩滃ぇ浜庣偣鐨勪釜鏁帮紝鍥犳鍙互鐪嬫垚鏃堕棿澶嶆潅搴︽槸O(E)

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02

鈥?/span>

娣卞害浼樺厛

娣卞害浼樺厛绠楁硶濡傚悓璧拌糠瀹紝鎴戜滑闅忔剰閫夋嫨涓€涓矓璺潵璧?/p>

褰撳彂鐜拌蛋涓嶉€氫簡锛屽啀閫€鍥炲埌涓婁竴涓矓璺彛锛岄噸鏂伴€夋嫨涓€鏉¤矾璧?/p>

鐩村埌鎵惧埌鏈€鍚庣殑鍑哄彛銆?br>

濡傚浘锛?/p>

浠ｇ爜锛?/strong>

boolean found = false; // 鍏ㄥ眬鍙橀噺鎴栬€呯被鎴愬憳鍙橀噺
public void dfs(int s, int t) { found = false; boolean[] visited = new boolean[v]; int[] prev = new int[v]; for (int i = 0; i < v; ++i) { prev[i] = -1; } recurDfs(s, t, visited, prev); print(prev, s, t);}
private void recurDfs(int w, int t, boolean[] visited, int[] prev) { if (found == true) return; visited[w] = true; if (w == t) { found = true; return; } for (int i = 0; i < adj[w].size(); ++i) { int q = adj[w].get(i); if (!visited[q]) { prev[q] = w; recurDfs(q, t, visited, prev); } }}

娣卞害浼樺厛姣忔潯杈硅嚦灏戜細閬嶅巻涓ゆ鍥犳澶嶆潅搴︽槸O(E)

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03

鈥?/span>

鎬荤粨

骞垮害浼樺厛锛氭槸浠庤捣濮嬬偣寮€濮嬶紝鍦版寮忔悳绱紝闇€瑕佸€熷姪闃熷垪鏉ュ疄鐜般€?/p>

娣卞害浼樺厛锛氶渶瑕佸洖婧€濇兂锛屽€熷姪閫掑綊鏉ュ疄鐜般€?/p>

浜岃€呮椂闂村鏉傚害閮芥槸O(E)