Notes

// public String fractionAddition(String expression) {
// Scanner sc = new Scanner(expression).useDelimiter("/|(?=[-+])");
// int A = 0, B = 1;
// while (sc.hasNext()) {
// int a = sc.nextInt(), b = sc.nextInt();
// A = A * b + a * B;
// B *= b;
// int g = gcd(A, B);
// A /= g;
// B /= g;
// }
// return A + "/" + B;
// }

// private int gcd(int a, int b) {
// return a != 0 ? gcd(b % a, a) : Math.abs(b);
// }

// https://discuss.leetcode.com/topic/90061/small-simple-c-java-python/2
// private long gcd(long a, long b) {
// if (b == 0)
// return a < 0 ? -a : a; // always return positive gcd
// return gcd(b, a % b);
// }
class Solution {
public int countHoles (int num) {
int[] holes = new int[] {1, 0, 0, 0, 1, 0, 1, 2, 1};
char[] arr = String.valueOf(num).toCharArray();

int count = 0;
for (char ch : arr) {
count += holes[ch - '0'];
}

return count;
}

public int[] getMin(String[] a, String[] b) {
if (a == null || b == null) {
return new int[];
}

int[] results = new int[a.length];

for (int i = 0; i < a.length; i++) {
String s1 = a[i];
String s2 = b[i];

if (s1.length() != s2.length()) {
results[i] = -1;
continue;
}

HashMap<Character, Integer> charCount = new HashMap<>();

for (int j = 0; j < s1.length(); j++) {
char c1 = s1.charAt(j);
char c2 = s2.charAt(j);
if (charCount.get(c1) != null) {
charCount.put(c1, charCount.get(c1) + 1);
} else {
charCount.put(c1, 1);
}
if (charCount.get(c2) != null) {
charCount.put(c2, charCount.get(c2) - 1);
} else {
charCount.put(c1, -1);
}
}


for(Integer n : charCount.values()) {
results[i] += Math.abs(n);
}

results[i] /= 2;
}

return results;
}

public long countSteps(String[] steps) {
// if (steps == null || steps.length == 0) {
// return 0;
// }

int minR = Integer.MAX_VALUE;
int minC = Integer.MAX_VALUE;

for (String step : steps) {
String[] rc = step.split(" ");
int r = Integer.valueOf(rc[0]);
int c = Integer.valueOf(rc[1]);
minR = Math.min(minR, r);
minC = Math.min(minC, c);
}

return (long) minC * (long) minR;
}

public String[] reduced(String[] expressions) {
if (expressions == null || expressions.length == 0) {
return new String[];
}

String[] results = new String[expressions.length];

for (int i = 0; i < expressions.length; i++) {
String[] cur = expressions[i].split("[+/]");
int a = Integer.valueOf(cur[0]);
int b = Integer.valueOf(cur[1]);
int c = Integer.valueOf(cur[2]);
int d = Integer.valueOf(cur[3]);

int n = a * d + b * c;
int d = b * d;
int g = gcd(n, d);
n /= g;
d /= g;
results[i] = n + "/" + d;
}

}

private int gcd(int a, int b) {
if (a == 0) {
return Math.abs(b);
}
return gcd(a % b, b);
}
}


var lengthOfLIS = function(nums) {
const dp = new Array(nums.length).fill(1);

for (let i = 1; i < nums.length; i++) {
for (let j = 0; j < i; j++) {
if (nums[j] < nums[i]) {
dp[i] = Math.max(dp[i], dp[j] + 1);
}
}
}

return Math.max(0, ...dp);
};

http://www.1point3acres.com/bbs/forum.php?mod=viewthread&tid=286040&highlight=ixl


public int maxHeight(int[] predators){

int n = predators.length;
int[] res = new int[n];
Arrays.fill(res, 1);

for (int i = 0; i < n; i++){
int dir = predators[i];
if (dir == -1){
continue;
}else{
int pre = i;
while (dir != -1){
res[dir] = Math.max(res[dir], res[pre]+1);
pre = dir;
dir = predators[dir];
}
}. From 1point 3acres bbs
}

int max = 0;
for (int number: res){
max = Math.max(max, number);
}

return max;

}

public class Solution {
public int lengthOfLIS(int[] nums) {
int[] dp = new int[nums.length];
int len = 0;

for(int x : nums) {
int i = Arrays.binarySearch(dp, 0, len, x);
if(i < 0) i = -(i + 1);
dp[i] = x;
if(i == len) len++;
}

return len;
}
}