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Merge pull request #1324 from lizhendong128/master

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更新了0059.螺旋矩阵II的Java版本和0150.逆波兰表达式求值的Java版本
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程序员Carl
2022-06-02 08:39:56 +08:00
committed by GitHub
parent 9c537e9395 8dbe3b6830
commit f03f8d2b61
2 changed files with 18 additions and 38 deletions
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44
problems/0059.螺旋矩阵II.md
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@ -130,57 +130,37 @@ Java：
```Java ```Java
class Solution { class Solution {
public int[][] generateMatrix(int n) { public int[][] generateMatrix(int n) {
int loop = 0; // 控制循环次数
int[][] res = new int[n][n]; int[][] res = new int[n][n];
int start = 0; // 每次循环的开始点(start, start)
int count = 1; // 定义填充数字
int i, j;
// 循环次数 while (loop++ < n / 2) { // 判断边界后，loop从1开始
int loop = n / 2;
// 定义每次循环起始位置
int startX = 0;
int startY = 0;
// 定义偏移量
int offset = 1;
// 定义填充数字
int count = 1;
// 定义中间位置
int mid = n / 2;
while (loop > 0) {
int i = startX;
int j = startY;
// 模拟上侧从左到右 // 模拟上侧从左到右
for (; j<startY + n -offset; ++j) { for (j = start; j < n - loop; j++) {
res[startX][j] = count++; res[start][j] = count++;
} }
// 模拟右侧从上到下 // 模拟右侧从上到下
for (; i<startX + n -offset; ++i) { for (i = start; i < n - loop; i++) {
res[i][j] = count++; res[i][j] = count++;
} }
// 模拟下侧从右到左 // 模拟下侧从右到左
for (; j > startY; j--) { for (; j >= loop; j--) {
res[i][j] = count++; res[i][j] = count++;
} }
// 模拟左侧从下到上 // 模拟左侧从下到上
for (; i > startX; i--) { for (; i >= loop; i--) {
res[i][j] = count++; res[i][j] = count++;
} }
start++;
loop--;
startX += 1;
startY += 1;
offset += 2;
} }
if (n % 2 == 1) { if (n % 2 == 1) {
res[mid][mid] = count; res[start][start] = count;
} }
return res; return res;

12
problems/0150.逆波兰表达式求值.md
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@ -136,19 +136,19 @@ java:
class Solution { class Solution {
public int evalRPN(String[] tokens) { public int evalRPN(String[] tokens) {
Deque<Integer> stack = new LinkedList(); Deque<Integer> stack = new LinkedList();
for (int i = 0; i < tokens.length; ++i) { for (String s : tokens) {
if ("+".equals(tokens[i])) { // leetcode 内置jdk的问题，不能使用==判断字符串是否相等 if ("+".equals(s)) { // leetcode 内置jdk的问题，不能使用==判断字符串是否相等
stack.push(stack.pop() + stack.pop()); // 注意 - 和/ 需要特殊处理 stack.push(stack.pop() + stack.pop()); // 注意 - 和/ 需要特殊处理
} else if ("-".equals(tokens[i])) { } else if ("-".equals(s)) {
stack.push(-stack.pop() + stack.pop()); stack.push(-stack.pop() + stack.pop());
} else if ("*".equals(tokens[i])) { } else if ("*".equals(s)) {
stack.push(stack.pop() * stack.pop()); stack.push(stack.pop() * stack.pop());
} else if ("/".equals(tokens[i])) { } else if ("/".equals(s)) {
int temp1 = stack.pop(); int temp1 = stack.pop();
int temp2 = stack.pop(); int temp2 = stack.pop();
stack.push(temp2 / temp1); stack.push(temp2 / temp1);
} else { } else {
stack.push(Integer.valueOf(tokens[i])); stack.push(Integer.valueOf(s));
} }
} }
return stack.pop(); return stack.pop();