线段树-入门 - 代码物语-Let code talk - ITeye技术网站


线段树-入门 - 代码物语-Let code talk - ITeye技术网站

  •  * 问题:已知线段[2,5] [4,6] [0,7];求点2,4,7分别出现了多少次 
  •  * 以下代码建立的线段树用链表来保存,且树的叶子结点类似[i,i] 

    1. public class SegmentTreeLearn {  
    2.   
    3.     public static void main(String[] args) {  
    4.         SegmentTree tree = new SegmentTree(07);  
    5.         int[][] segments = {  
    6.                 {25},   
    7.                 {46},   
    8.                 {07}  
    9.         };  
    10.         int[] targets = {247};  
    11.         for (int i = 0, len = segments.length; i < len; i++) {  
    12.             int[] segment = segments[i];  
    13.             tree.insert(segment[0], segment[1]);  
    14.         }  
    15.         for(int target : targets) {  
    16.             System.out.println(target + ":" + tree.caculateExistingTimes(target));  
    17.         }  
    18.     }  
    19.       
    20.   
    21.   
    22. }  
    23.   
    24. class SegmentTree {  
    25.   
    26.     //递归定义的,因此很多操作都是递归实现  
    27.     private class Segment {  
    28.         int left;  
    29.         int right;  
    30.         int count;  
    31.         Segment leftChild;  
    32.         Segment rightChild;  
    33.     }  
    34.       
    35.     private Segment root;  
    36.       
    37.     public SegmentTree (int left, int right) {  
    38.         root = new Segment();  
    39.         build(root, left, right);  
    40.     }  
    41.       
    42.     public void insert(int left, int right) {  
    43.         insert(root, left, right);  
    44.     }  
    45.       
    46.     public int caculateExistingTimes(int target) {  
    47.         return caculateExistingTimes(root, target);  
    48.     }  
    49.       
    50.     //从根节点开始查找叶子结点[target, target],对经过的节点的count求和  
    51.     private int caculateExistingTimes(Segment root, int target) {  
    52.         int result = 0;  
    53.         while( root.left != root.right) {  
    54.             int rootMid = root.left + (root.right - root.left) / 2;  
    55.             result += root.count;  
    56.             if (target <= rootMid) {  
    57.                 root = root.leftChild;  
    58.             } else if (target > rootMid) {  
    59.                 root = root.rightChild;  
    60.             }  
    61.         }  
    62.         return result;  
    63.     }  
    64.      
    65.     private void build(Segment root, int left, int right) {  
    66.         root.left = left;  
    67.         root.right = right;  
    68.         if (left != right) {  
    69.             int mid = left + (right - left) / 2;  
    70.             root.leftChild = new Segment();  
    71.             root.rightChild = new Segment();  
    72.             build(root.leftChild, left, mid);  
    73.             build(root.rightChild, mid + 1, right);  
    74.         }  
    75.     }  
    76.       
    77.     private void insert(Segment root, int left, int right) {  
    78.           
    79.         int rootLeft = root.left;  
    80.         int rootRight = root.right;  
    81.         int rootMid = rootLeft + (rootRight - rootLeft) / 2;  
    82.           
    83.         //匹配,出现次数加1  
    84.         if (left == rootLeft && right == rootRight) {  
    85.             root.count++;  
    86.             return;  
    87.         }  
    88.           
    89.         if (right <= rootMid) {  
    90.             insert(root.leftChild, left, right);  
    91.         } else if (left > rootMid){  
    92.             insert(root.rightChild, left, right);  
    93.         } else {  
    94.             insert(root.leftChild, left, rootMid);  
    95.             insert(root.rightChild, rootMid + 1, right);  
    96.         }  
    97.     }  
    98.       
    99. }  
    Read full article from 线段树-入门 - 代码物语-Let code talk - ITeye技术网站

    Labels

    LeetCode (1432) GeeksforGeeks (1122) LeetCode - Review (1067) Review (882) Algorithm (668) to-do (609) Classic Algorithm (270) Google Interview (237) Classic Interview (222) Dynamic Programming (220) DP (186) Bit Algorithms (145) POJ (141) Math (137) Tree (132) LeetCode - Phone (129) EPI (122) Cracking Coding Interview (119) DFS (115) Difficult Algorithm (115) Lintcode (115) Different Solutions (110) Smart Algorithm (104) Binary Search (96) BFS (91) HackerRank (90) Binary Tree (86) Hard (79) Two Pointers (78) Stack (76) Company-Facebook (75) BST (72) Graph Algorithm (72) Time Complexity (69) Greedy Algorithm (68) Interval (63) Company - Google (62) Geometry Algorithm (61) Interview Corner (61) LeetCode - Extended (61) Union-Find (60) Trie (58) Advanced Data Structure (56) List (56) Priority Queue (53) Codility (52) ComProGuide (50) LeetCode Hard (50) Matrix (50) Bisection (48) Segment Tree (48) Sliding Window (48) USACO (46) Space Optimization (45) Company-Airbnb (41) Greedy (41) Mathematical Algorithm (41) Tree - Post-Order (41) ACM-ICPC (40) Algorithm Interview (40) Data Structure Design (40) Graph (40) Backtracking (39) Data Structure (39) Jobdu (39) Random (39) Codeforces (38) Knapsack (38) LeetCode - DP (38) Recursive Algorithm (38) String Algorithm (38) TopCoder (38) Sort (37) Introduction to Algorithms (36) Pre-Sort (36) Beauty of Programming (35) Must Known (34) Binary Search Tree (33) Follow Up (33) prismoskills (33) Palindrome (32) Permutation (31) Array (30) Google Code Jam (30) HDU (30) Array O(N) (29) Logic Thinking (29) Monotonic Stack (29) Puzzles (29) Code - Detail (27) Company-Zenefits (27) Microsoft 100 - July (27) Queue (27) Binary Indexed Trees (26) TreeMap (26) to-do-must (26) 1point3acres (25) GeeksQuiz (25) Merge Sort (25) Reverse Thinking (25) hihocoder (25) Company - LinkedIn (24) Hash (24) High Frequency (24) Summary (24) Divide and Conquer (23) Proof (23) Game Theory (22) Topological Sort (22) Lintcode - Review (21) Tree - Modification (21) Algorithm Game (20) CareerCup (20) Company - Twitter (20) DFS + Review (20) DP - Relation (20) Brain Teaser (19) DP - Tree (19) Left and Right Array (19) O(N) (19) Sweep Line (19) UVA (19) DP - Bit Masking (18) LeetCode - Thinking (18) KMP (17) LeetCode - TODO (17) Probabilities (17) Simulation (17) String Search (17) Codercareer (16) Company-Uber (16) Iterator (16) Number (16) O(1) Space (16) Shortest Path (16) itint5 (16) DFS+Cache (15) Dijkstra (15) Euclidean GCD (15) Heap (15) LeetCode - Hard (15) Majority (15) Number Theory (15) Rolling Hash (15) Tree Traversal (15) Brute Force (14) Bucket Sort (14) DP - Knapsack (14) DP - Probability (14) Difficult (14) Fast Power Algorithm (14) Pattern (14) Prefix Sum (14) TreeSet (14) Algorithm Videos (13) Amazon Interview (13) Basic Algorithm (13) Codechef (13) Combination (13) Computational Geometry (13) DP - Digit (13) LCA (13) LeetCode - DFS (13) Linked List (13) Long Increasing Sequence(LIS) (13) Math-Divisible (13) Reservoir Sampling (13) mitbbs (13) Algorithm - How To (12) Company - Microsoft (12) DP - Interval (12) DP - Multiple Relation (12) DP - Relation Optimization (12) LeetCode - Classic (12) Level Order Traversal (12) Prime (12) Pruning (12) Reconstruct Tree (12) Thinking (12) X Sum (12) AOJ (11) Bit Mask (11) Company-Snapchat (11) DP - Space Optimization (11) Dequeue (11) Graph DFS (11) MinMax (11) Miscs (11) Princeton (11) Quick Sort (11) Stack - Tree (11) 尺取法 (11) 挑战程序设计竞赛 (11) Coin Change (10) DFS+Backtracking (10) Facebook Hacker Cup (10) Fast Slow Pointers (10) HackerRank Easy (10) Interval Tree (10) Limited Range (10) Matrix - Traverse (10) Monotone Queue (10) SPOJ (10) Starting Point (10) States (10) Stock (10) Theory (10) Tutorialhorizon (10) Kadane - Extended (9) Mathblog (9) Max-Min Flow (9) Maze (9) Median (9) O(32N) (9) Quick Select (9) Stack Overflow (9) System Design (9) Tree - Conversion (9) Use XOR (9) Book Notes (8) Company-Amazon (8) DFS+BFS (8) DP - States (8) Expression (8) Longest Common Subsequence(LCS) (8) One Pass (8) Quadtrees (8) Traversal Once (8) Trie - Suffix (8) 穷竭搜索 (8) Algorithm Problem List (7) All Sub (7) Catalan Number (7) Cycle (7) DP - Cases (7) Facebook Interview (7) Fibonacci Numbers (7) Flood fill (7) Game Nim (7) Graph BFS (7) HackerRank Difficult (7) Hackerearth (7) Inversion (7) Kadane’s Algorithm (7) Manacher (7) Morris Traversal (7) Multiple Data Structures (7) Normalized Key (7) O(XN) (7) Radix Sort (7) Recursion (7) Sampling (7) Suffix Array (7) Tech-Queries (7) Tree - Serialization (7) Tree DP (7) Trie - Bit (7) 蓝桥杯 (7) Algorithm - Brain Teaser (6) BFS - Priority Queue (6) BFS - Unusual (6) Classic Data Structure Impl (6) DP - 2D (6) DP - Monotone Queue (6) DP - Unusual (6) DP-Space Optimization (6) Dutch Flag (6) How To (6) Interviewstreet (6) Knapsack - MultiplePack (6) Local MinMax (6) MST (6) Minimum Spanning Tree (6) Number - Reach (6) Parentheses (6) Pre-Sum (6) Probability (6) Programming Pearls (6) Rabin-Karp (6) Reverse (6) Scan from right (6) Schedule (6) Stream (6) Subset Sum (6) TSP (6) Xpost (6) n00tc0d3r (6) reddit (6) AI (5) Abbreviation (5) Anagram (5) Art Of Programming-July (5) Assumption (5) Bellman Ford (5) Big Data (5) Code - Solid (5) Code Kata (5) Codility-lessons (5) Coding (5) Company - WMware (5) Convex Hull (5) Crazyforcode (5) DFS - Multiple (5) DFS+DP (5) DP - Multi-Dimension (5) DP-Multiple Relation (5) Eulerian Cycle (5) Graph - Unusual (5) Graph Cycle (5) Hash Strategy (5) Immutability (5) Java (5) LogN (5) Manhattan Distance (5) Matrix Chain Multiplication (5) N Queens (5) Pre-Sort: Index (5) Quick Partition (5) Quora (5) Randomized Algorithms (5) Resources (5) Robot (5) SPFA(Shortest Path Faster Algorithm) (5) Shuffle (5) Sieve of Eratosthenes (5) Strongly Connected Components (5) Subarray Sum (5) Sudoku (5) Suffix Tree (5) Swap (5) Threaded (5) Tree - Creation (5) Warshall Floyd (5) Word Search (5) jiuzhang (5)

    Popular Posts