JZ-C-22

剑指offer第二十二题：栈的压入、弹出序列

  1 //============================================================================
  2 // Name        : JZ-C-22.cpp
  3 // Author      : Laughing_Lz
  4 // Version     :
  5 // Copyright   : All Right Reserved
  6 // Description : 栈的压入、弹出序列
  7 //============================================================================
  8
  9 #include <iostream>
 10 #include <stdio.h>
 11 #include <stack>
 12 using namespace std;
 13 /**
 14  *给定两个整数序列，第一个序列表示栈的压入顺序，判断第二个序列是否会是该栈的弹出顺序
 15  */
 16 bool IsPopOrder(const int* pPush, const int* pPop, int nLength) {
 17     std::stack<int> StackData; //辅助栈
 18     if (pPush != NULL && pPop != NULL && nLength != 0) {
 19         int pLength = nLength-1;//pLength指的是压入栈剩余未进辅助栈的数目
 20         StackData.push(*pPush);
 21         while (!StackData.empty()) { //每次将辅助栈的栈顶元素和弹出栈序列第一个数比较,直至全部比较完毕
 22             if (StackData.top() != *pPop && pLength > 0) {
 23                 pPush++;
 24                 StackData.push(*pPush);
 25                 pLength--;
 26             } else if (StackData.top() != *pPop && pLength <= 0) {
 27                 return false; //弹出栈序列有错误，直接退出循环
 28             } else {
 29                 StackData.pop();
 30                 pPop++;
 31                 if(StackData.empty() && pLength > 0){//出栈后若辅助栈为空，继续压入‘压入栈序列’后续元素
 32                     StackData.push(*pPush);
 33                 }
 34             }
 35         }
 36     } else {
 37         return false;
 38     }
 39     return true;
 40 }
 41
 42 // ====================测试代码====================
 43 void Test(char* testName, const int* pPush, const int* pPop, int nLength,
 44         bool expected) {
 45     if (testName != NULL)
 46         printf("%s begins: ", testName);
 47
 48     if (IsPopOrder(pPush, pPop, nLength) == expected)
 49         printf("Passed.\n");
 50     else
 51         printf("failed.\n");
 52 }
 53
 54 void Test1() {
 55     const int nLength = 5;
 56     int push[nLength] = { 1, 2, 3, 4, 5 };
 57     int pop[nLength] = { 4, 5, 3, 2, 1 };
 58
 59     Test("Test1", push, pop, nLength, true);
 60 }
 61
 62 void Test2() {
 63     const int nLength = 5;
 64     int push[nLength] = { 1, 2, 3, 4, 5 };
 65     int pop[nLength] = { 3, 5, 4, 2, 1 };
 66
 67     Test("Test2", push, pop, nLength, true);
 68 }
 69
 70 void Test3() {
 71     const int nLength = 5;
 72     int push[nLength] = { 1, 2, 3, 4, 5 };
 73     int pop[nLength] = { 4, 3, 5, 1, 2 };
 74
 75     Test("Test3", push, pop, nLength, false);
 76 }
 77
 78 void Test4() {
 79     const int nLength = 5;
 80     int push[nLength] = { 1, 2, 3, 4, 5 };
 81     int pop[nLength] = { 3, 5, 4, 1, 2 };
 82
 83     Test("Test4", push, pop, nLength, false);
 84 }
 85
 86 // push和pop序列只有一个数字
 87 void Test5() {
 88     const int nLength = 1;
 89     int push[nLength] = { 1 };
 90     int pop[nLength] = { 2 };
 91
 92     Test("Test5", push, pop, nLength, false);
 93 }
 94
 95 void Test6() {
 96     const int nLength = 1;
 97     int push[nLength] = { 1 };
 98     int pop[nLength] = { 1 };
 99
100     Test("Test6", push, pop, nLength, true);
101 }
102
103 void Test7() {
104     Test("Test7", NULL, NULL, 0, false); //这里若两栈均为空，判断为false
105 }
106
107 void Test8() {
108     const int nLength = 5;
109     int push[nLength] = { 1, 2, 3, 4, 5 };
110     int pop[nLength] = { 1, 5, 4, 3, 2 };
111
112     Test("Test8", push, pop, nLength, true);
113 }
114 int main(int argc, char** argv) {
115     Test1();
116     Test2();
117     Test3();
118     Test4();
119     Test5();
120     Test6();
121     Test7();
122     Test8();
123
124     return 0;
125 }