Hi all,
I had a phone interview with google back in mid September last year. Here are the questions:
1. Given an array of words and a length L, format the text such that each line has exactly L characters and is fully (left and right) justified. You should pack your words in a greedy approach; that is, pack as many words as you can in each line. Pad extra spaces ' ' when necessary so that each line has exactly L characters. Extra spaces between words should be distributed as evenly as possible. If the number of spaces on a line do not divide evenly between words, the empty slots on the left will be assigned more spaces than the slots on the right. For the last line of text, it should be left justified and no extra space is inserted between words. For example, words: ["This", "is", "an", "example", "of", "text", "justification."] L: 16. Return the formatted lines as: [ "This is an", "example of text", "justification. " ]
public class Solution {
public ArrayList<String> fullJustify(String[] words, int L) {
int wordsCount = words.length;
ArrayList<String> result = new ArrayList<String>();
int curLen = 0;
int lastI = 0;
for (int i = 0; i <= wordsCount; i++) {
if (i == wordsCount || curLen + words[i].length() + i - lastI > L) {
StringBuffer buf = new StringBuffer();
int spaceCount = L - curLen;
int spaceSlots = i - lastI - 1;
if (spaceSlots == 0 || i == wordsCount) {
for(int j = lastI; j < i; j++){
buf.append(words[j]);
if(j != i - 1)
appendSpace(buf, 1);
}
appendSpace(buf, L - buf.length());
} else {
int spaceEach = spaceCount / spaceSlots;
int spaceExtra = spaceCount % spaceSlots;
for (int j = lastI; j < i; j++) {
buf.append(words[j]);
if (j != i - 1)
appendSpace(buf, spaceEach + (j - lastI < spaceExtra ? 1 : 0));
}
}
lastI = i;
curLen = 0;
}
if (i < wordsCount)
curLen += words[i].length();
}
return result;
}

private void appendSpace(StringBuffer sb, int count) {
for (int i = 0; i < count; i++)
sb.append(' ';
}
}
2. You are climbing a stair case. It takes n steps to reach to the top. Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?
public class Solution {
public int climbStairs(int n) {
if (n <= 1) {
return 1;
}
int last = 1, lastlast = 1;
int now = 0;
for (int i = 2; i <= n; i++) {
now = last + lastlast;
lastlast = last;
last = now;
}
return now;
}
}