http://www.1point3acres.com/bbs/forum.php?mod=viewthread&tid=290480&highlight=zenefits

http://www.1point3acres.com/bbs/forum.php?mod=viewthread&tid=287729&highlight=zenefits

Print Diamond

没想到巧妙的办法

public class PrintSymbol {

//    Question1: print
//                 *   0 - 1 6
//                ***  1 - 3 4
//               ***** 2 - 5 2
//              *******3 - 7 0
//               ***** 4 - 5 2
//                ***  5 - 3 4
//                 *   6 - 1 6

    public static void printSymbol(int row) {
        int max = row * 2 - 1;
        int print;
        int space;
        int print2;
        int space2 = 0;

        for (int i = 0; i < row * 2 - 1; ++i) {

            if (i < row) {
                print = i * 2 + 1;
                space = (max - print) / 2;
                for (int j = 0; j < space; ++j) {
                    System.out.print(" ");
                }
                for (int j = 0; j < print; ++j) {
                    System.out.print("*");
                }
                for (int j = 0; j < space; ++j) {
                    System.out.print(" ");
                }
                System.out.println();
            } else {
                space2 += 1;
                print2 = max - space2 * 2;
                for (int j = 0; j < space2; ++j) {
                    System.out.print(" ");
                }
                for (int j = 0; j < print2; ++j) {
                    System.out.print("*");
                }
                for (int j = 0; j < space2; ++j) {
                    System.out.print(" ");
                }
                System.out.println();
            }
        }
    }
    public static void main(String[] args) {
        printSymbol(3);
    }
}

635. Design Log Storage System

class LogSystem {

    List<String[]> timestamps;
    List<String> time = Arrays.asList("Year", "Month", "Day", "Hour", "Minute", "Second");
    int[] indices = {4, 7, 10, 13, 16, 19};
    public LogSystem() {
        timestamps = new LinkedList<>();

    }

    public void put(int id, String timestamp) {
        timestamps.add(new String[] {Integer.toString(id), timestamp});
    }

    public List<Integer> retrieve(String s, String e, String gra) {
        List<Integer> result = new LinkedList<>();
        int index = indices[time.indexOf(gra)];
        for (String[] timestamp : timestamps) {
            if (timestamp[1].substring(0, index).compareTo(s.substring(0, index)) >= 0
               && timestamp[1].substring(0, index).compareTo(e.substring(0, index)) <= 0)                                                           result.add(Integer.parseInt(timestamp[0]));
        }
        return result;
    }
}

409. Longest Palindrome

class Solution {
    public int longestPalindrome(String s) {
        int[] hash = new int[256];
        char[] chars = s.toCharArray();
        for (int i = 0; i < chars.length; ++i) {
            hash[chars[i]]++;
        }
        int count = 0;
        boolean flag = false;
        for (int i = 0; i < hash.length; ++i) {
            if (hash[i] != 0) {
                if (hash[i] % 2 == 0) {
                    count += hash[i];
                } else {
                    count += hash[i] - 1;
                    flag = true;
                }
            }
        }
        return flag ? count + 1 : count;
    }
}

155. Min Stack

public class minStack {

    Stack<Integer> stack;
    Stack<Integer> minStack;

    /**
     * initialize your data structure here.
     */
    public void MinStack() {
        stack = new Stack<>();
        minStack = new Stack<>();
    }

    public void push(int x) {
        stack.push(x);
        if (minStack.isEmpty()) {
            minStack.push(x);
        } else minStack.push(Math.min(x, minStack.peek()));
    }

    public void pop() {
        stack.pop();
        minStack.pop();
    }

    public int top() {
        return stack.peek();
    }

    public int getMin() {
        return minStack.peek();
    }
}