884.比较含退格的字符串
给定 s 和 t 两个字符串，当它们分别被输入到空白的文本编辑器后，如果两者相等，返回 true 。# 代表退格字符。
注意：如果对空文本输入退格字符，文本继续为空。
方法一、用栈
#include <iostream>
#include <stack>
#include <string>using namespace std;bool backspaceCompare(string s, string t) {stack<char> stack_s, stack_t;// Process string sfor (char c : s) {if (c != '#') {stack_s.push(c);} else if (!stack_s.empty()) {stack_s.pop();}}// Process string tfor (char c : t) {if (c != '#') {stack_t.push(c);} else if (!stack_t.empty()) {stack_t.pop();}}// Compare the resulting stringsstring result_s, result_t;while (!stack_s.empty()) {result_s += stack_s.top();stack_s.pop();}while (!stack_t.empty()) {result_t += stack_t.top();stack_t.pop();}return result_s == result_t;
}int main() {string s = "ab#c";string t = "ad#c";if (backspaceCompare(s, t)) {cout << "The strings are equal." << endl;} else {cout << "The strings are not equal." << endl;}return 0;
}
方法二、双指针
#include <iostream>
#include <string>using namespace std;bool backspaceCompare(string s, string t) {int i = s.size() - 1, j = t.size() - 1;int skipS = 0, skipT = 0;while (i >= 0 || j >= 0) {// Find position to compare in string swhile (i >= 0) {if (s[i] == '#') {skipS++;i--;} else if (skipS > 0) {skipS--;i--;} else {break;}}// Find position to compare in string twhile (j >= 0) {if (t[j] == '#') {skipT++;j--;} else if (skipT > 0) {skipT--;j--;} else {break;}}// Compare charactersif (i >= 0 && j >= 0 && s[i] != t[j]) {return false;}// Check if one string has reached its end while the other hasn'tif ((i >= 0) != (j >= 0)) {return false;}i--;j--;}return true;
}int main() {string s = "ab#c";string t = "ad#c";if (backspaceCompare(s, t)) {cout << "The strings are equal." << endl;} else {cout << "The strings are not equal." << endl;}return 0;
}
977.有序数组平方
给你一个按 非递减顺序 排序的整数数组 nums，返回 每个数字的平方 组成的新数组，要求也按 非递减顺序 排序。
#include <iostream>
#include <vector>using namespace std;vector<int> sortedSquares(vector<int>& nums) {int n = nums.size();vector<int> result(n);int left = 0, right = n - 1;int index = n - 1; // Index to insert the largest squarewhile (left <= right) {int square_left = nums[left] * nums[left];int square_right = nums[right] * nums[right];if (square_left > square_right) {result[index--] = square_left;left++;} else {result[index--] = square_right;right--;}}return result;
}int main() {vector<int> nums = {-4, -1, 0, 3, 10};vector<int> result = sortedSquares(nums);cout << "Sorted squares: ";for (int num : result) {cout << num << " ";}cout << endl;return 0;
})
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