练习一:替换所有的问号
[1576. 替换所有的问号]
class Solution { public String modifyString(String s) { char[] ch = s.toCharArray(); for(int i=0;i<ch.length;i++){ if(ch[i] == '?'){ for(char tmp = 'a';tmp<='z';tmp++){ if((i == 0||tmp!=ch[i-1])&&(i ==ch.length-1||tmp!=ch[i+1])){ ch[i] = tmp; break; } } } } return String.valueOf(ch); } }
练习二:提莫攻击
[495. 提莫攻击]
class Solution { public int findPoisonedDuration(int[] nums, int duration) { int ret = 0; for(int i=0;i<nums.length;i++){ if((i == nums.length-1)||(nums[i+1]-nums[i]>=duration)){ ret+=duration; }else{ ret+=nums[i+1]-nums[i]; } } return ret; } }
练习三:Z 字形变换
[6. Z 字形变换]

