劍指offer編程題java實現

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面試題三：尋找二維數組中元素問題

 public static void main(String[] args){
         int[][] num = {{1,2,8,9},{2,4,9,12},{4,7,10,13},{6,8,11,15}};
        search(num,7);
        
     }
      public static void search(int[][] arr,int target){
          int rows = arr.length;
          int columns = arr[0].length;
          int row = 0;
          int column = columns-1;
          
          while(row<=rows&&column>=0){
          if(target==arr[row][column]){
              System.out.println(target+"在第"+row+"行，第"+column+"列");
              break;
            }
          if(target>arr[row][column]){
              row++;
          }
          if(target<arr[row][column]){
              column--;
          }
         }
      }

面試題四：替換字串中的空格

 public static void main(String[] args){         int[][] num = {{1,2,8,9},{2,4,9,12},{4,7,10,13},{6,8,11,15}};          String str = "we are happy";          replaceBlank(str);              }            public static void replaceBlank(String str){                  char[] charOld = str.toCharArray();         char[] charNew = new char[100];         for(int j = 0;j<charOld.length;j++){             charNew[j] = charOld[j];         }         int blank = 0;          for(int i = 0;i<charNew.length;i++){              if(charNew[i]==‘ ‘){                  blank++;              }          }          int lengthFront = charOld.length-1;                    int lengthBack = charOld.length+2*blank-1;                    while(lengthFront>=0&&lengthBack>=0){              if(charNew[lengthFront]!=‘ ‘){                  charNew[lengthBack--] = charNew[lengthFront];              }              else               {                  charNew[lengthBack--] = ‘0‘;                  charNew[lengthBack--] = ‘2‘;                  charNew[lengthBack--] = ‘%‘;                  lengthFront--;              }              lengthFront--;          }          System.out.println(charNew);                         }

 

劍指offer編程題java實現