09月21日, 2014 47次
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 |
// // //代码出自“脑客爱刷题”www.knockgate.com，转载请注明出处 package codeforclass; import java.util.HashMap; import java.util.LinkedList; import java.util.List; import java.util.Map.Entry; public class FindMajorityNumberInArray { public static void printHalfMajorNum(int[] test) { int mayBeNum = 0; int appearTimes = 0; for (int i = 0; i != test.length; i++) { if (appearTimes == 0) { mayBeNum = test[i]; appearTimes = 1; } else if (test[i] == mayBeNum) { appearTimes++; } else { appearTimes--; } } appearTimes = 0; for (int i = 0; i != test.length; i++) { if (test[i] == mayBeNum) { appearTimes++; } } System.out.println(appearTimes > test.length / 2 ? "More than half element: " + mayBeNum : "No such number!"); } public static void printKMajorNumber(int[] test, int K) { if (K < 2) { System.out.println("The value of K is invalid."); return; } HashMap<Integer, Integer> map = new HashMap<Integer, Integer>(); for (int i = 0; i != test.length; i++) { if (map.containsKey(test[i])) { Integer value = map.get(test[i]); map.put(test[i], value + 1); } else { if (map.size() == K - 1) { allCandidateSubtractOne(map); } else { map.put(test[i], 1); } } } System.out.print("More than length/k element: "); for (Entry<Integer, Integer> set : map.entrySet()) { Integer key = set.getKey(); if (checkCandidateValid(test, key, K)) { System.out.print(key + " "); } } } public static void allCandidateSubtractOne(HashMap<Integer, Integer> map) { List<Integer> removeList = new LinkedList<Integer>(); for (Entry<Integer, Integer> set : map.entrySet()) { Integer key = set.getKey(); Integer value = set.getValue(); if (value == 1) { removeList.add(key); } map.put(key, value - 1); } for (Integer removeKey : removeList) { map.remove(removeKey); } } public static boolean checkCandidateValid(int[] test, int candidate, int K) { int times = 0; for (int i = 0; i != test.length; i++) { if (test[i] == candidate) { times++; } } return times > test.length / K ? true : false; } public static void main(String[] args) { int[] test1 = { 1, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 2 }; printHalfMajorNum(test1); int[] test2 = { 1, 2, 2, 1, 3, 3, 1 }; int K = 3; printKMajorNumber(test2, K); } } |
