3月6号 学而思

1.两个字符串的最大公共子串

int dp(char str1[], char str2[]) {
int min = 0;
int dp[][] = new int[str1.length][str2.length];

for (int i = 0; i < str1.length; i++) {
if (str1[i] == str2[0])
dp[i][0] = 1;
else
dp[i][0] = 0;
}

for (int i = 0; i < str2.length; i++) {
if (str1[0] == str2[i])
dp[0][i] = 1;
else
dp[0][i] = 0;
}

for (int i = 1; i < str1.length; i++) {
for (int j = 1; j < str2.length; j++) {
if (str1[i] == str2[j])
dp[i][j] = dp[i - 1][j - 1] + 1;
else
dp[i][j] = 0;
}
}

for (int i = 0; i < str1.length; i++) {
for (int j = 0; j < str2.length; j++) {
if (dp[i][j] > min)
min = dp[i][j];
}
}

return min;
}

2.strsplit函数的实现

3.小根堆的实现

4.不用额外空间，交换两个数据

int a = 10;
int b = 5;
a = a + b;
b = a - b;
a = a - b;

int a = x, b = y;   //两个相同的数异或结果为0，任何数与0异或的结果是任何数
a = a ^ b;          //a = x ^ y;
b = b ^ a;          //b = y ^ x ^ y = x;
a = a ^ b;          //a = x ^ y ^ x = y;