目录
替换所有问号
提莫攻击
Z字形变换
外观数列
数青蛙
替换所有问号
替换所有问号
public String modifyString(String s) { char[] s1 = s.toCharArray(); int n = s.length(); for(int i = 0 ; i < n; i++){ if(s1[i] == '?'){ for(char ch = 'a' ; ch <= 'z'; ch++ ){ if((i == 0 || ch != s1[i - 1]) && (i == n - 1 || ch != s1[i + 1])){ s1[i] = ch; break; } } } } return String.valueOf(s1); }提莫攻击
提莫攻击
public int findPoisonedDuration(int[] timeSeries, int duration) { int ret = 0; for(int i = 1 ; i < timeSeries.length ; i++){ int x = timeSeries[i] - timeSeries[i - 1]; if( x >= duration) ret += duration; else ret += x; } return ret + duration ; }Z字形变换
Z字形变换
public String convert(String s, int numRows) { int d = 2 * numRows - 2,n = s.length(); StringBuilder ret = new StringBuilder(); if(numRows == 1) return s; for(int i = 0; i<n ; i+=d) ret.append(s.charAt(i)); for(int k = 1;k<numRows - 1 ; k++){ for(int i = k, j = d - i;j<n || i<n ; i+=d,j+=d){ if(i < n) ret.append(s.charAt(i)); if(j < n) ret.append(s.charAt(j)); } } for(int i = numRows - 1; i<n ; i+=d) ret.append(s.charAt(i)); return ret.toString(); }外观数列
外观数列
public String countAndSay(int n) { String ret = "1"; for(int i = 1 ; i < n ; i++ ){ StringBuilder tmp = new StringBuilder(); int len = ret.length(); for(int left = 0,right = 0; right < len; ){ while(right < len && ret.charAt(left) == ret.charAt(right)) right++; tmp.append(Integer.toString(right - left)); tmp.append(ret.charAt(left)); left = right; } ret = tmp.toString(); } return ret; }数青蛙
数青蛙
public int minNumberOfFrogs(String croakOfFrogs) { char[] c = croakOfFrogs.toCharArray(); String t = "croak"; int n = t.length(); int[] hash = new int[n]; Map<Character , Integer> index = new HashMap<>(); for(int i = 0 ; i < n ; i++){ index.put(t.charAt(i) , i); } for(char ch : c){ if(ch == t.charAt(0)){ if(hash[n - 1] != 0) hash[n - 1]--; hash[0]++; }else{ int i = index.get(ch); if(hash[i - 1] == 0) return - 1; hash[i - 1]--; hash[i]++; } } for(int i = 0; i < n - 1 ; i++){ if(hash[i] != 0) return -1; } return hash[n - 1]; }
