使用Java+Kotlin双语言的LeetCode刷题之路（一）

LeetCode learning records based on Java,Kotlin,Python...Github 地址

序号对应 LeetCode 中题目序号

1 两数之和

给定一个整数数列，找出其中和为特定值的那两个数,你可以假设每个输入都只会有一种答案，同样的元素不能被重用;

• Java 语言实现

public int[] twoSum(int[] nums, int target) {
int i, j;
for (i = 0; i < nums.length; i++) {
for (j = i + 1; j < nums.length; j++) {
int sun = nums[i] + nums[j];
if (target == sun) {
return new int[]{i, j};
}
}
}
return new int[]{-1, -1};
}


• Kotlin 语言实现

fun twoSum(nums: IntArray, target: Int): IntArray {
var sum: Int
for (i: Int in nums.indices) {
for (j: Int in i+1 until nums.lastIndex+1) {
sum = nums[i] + nums[j]
if (target == sum) {
return intArrayOf(i,j)
}
}
}
return intArrayOf(-1,-1)
}


7 给定一个范围为 32 位 int 的整数，将其颠倒

• Java 语言实现

public static int reverse(int x) {
int result;
int startLen = 0;
String str = String.valueOf(x);
if (str.charAt(0) == '-') {
startLen = 1;
}
if (str.length() == 1) {
return x;
}
int lastLen = str.length() - 1;
String readStr = "";
while (lastLen >= startLen) {
readStr = readStr + str.charAt(lastLen);
lastLen--;
}
try {
result = Integer.parseInt(readStr);
}catch (NumberFormatException e){
return 0;
}
return startLen == 0 ? result : result * (-1);
}


*Kotlin 语言实现

fun reverse(x: Int): Int {
var startLen = 0
if (x < 0) {
startLen = 1
}
val str = x.toString()
if (str.length == 1) {
return x
}
var lastLen = str.length - 1
var readStr = ""
while (lastLen >= startLen) {
readStr += str[lastLen]
lastLen--
}
return try {
if (startLen == 0) {
readStr.toInt()
} else {
readStr.toInt() * (-1)
}
} catch (e: NumberFormatException) {
0
}
}