Today is an example of The non-Designer's Design Book on bottom of Page 56 and Range Sum Query - Mutable on leetcode and leetcode's October LeetCoding Challenge with cpp.

BTW, I decided to have Saturday and Sunday as review days, so pressure of review doesn't get me down.

The non-Designer's Design Book

my answer:

• [F] color of green text
• [F] color of purple text
• [F] color of green background
• [F] font of green text

shit...

Range Sum Query - Mutable

Description

Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive.

The update(i, val) function modifies nums by updating the element at index i to val.

Example:

Given nums = [1, 3, 5]

sumRange(0, 2) -> 9
update(1, 2)
sumRange(0, 2) -> 8

Constraints:

• The array is only modifiable by the update function.
• You may assume the number of calls to update and sumRange function is distributed evenly.
• 0 <= i <= j <= nums.length - 1

Solution

using Binary Indexed Tree, I'll do it using segment tree for review.

class NumArray {
  vector<int> original;
  vector<int> bit;
  int lowbit(int x) {
    return x&(-x);
  }
  int sum(int x) {
    int ans = 0;
    while(x) {
      ans += bit[x];
      x -= lowbit(x);
    }
    return ans;
  }
  void add(int pos, int val) {
    while(pos < bit.size()) {
      bit[pos] += val;
      pos += lowbit(pos);
    }
  }
public:
  NumArray(vector<int>& nums) {
    original = nums;
    bit = vector<int>(nums.size()+1, 0);
    for (int i = 0; i < nums.size(); ++i) {
      add(i+1, nums[i]);
    }
  }
  
  void update(int i, int val) {
    int diff = val - original[i];
    original[i] = val;
    add(i+1, diff);
    return;
  }
  
  int sumRange(int i, int j) {
    return sum(j+1) - sum(i);
  }
};

October LeetCoding Challenge 5

Description

Complement of Base 10 Integer

Every non-negative integer N has a binary representation. For example, 5 can be represented as "101" in binary, 11 as "1011" in binary, and so on. Note that except for N = 0, there are no leading zeroes in any binary representation.

The complement of a binary representation is the number in binary you get when changing every 1 to a 0 and 0 to a 1. For example, the complement of "101" in binary is "010" in binary.

For a given number N in base-10, return the complement of it's binary representation as a base-10 integer.

Example 1:

Input: 5
Output: 2
Explanation: 5 is "101" in binary, with complement "010" in binary, which is 2 in base-10.

Example 2:

Input: 7
Output: 0
Explanation: 7 is "111" in binary, with complement "000" in binary, which is 0 in base-10.

Example 3:

Input: 10
Output: 5
Explanation: 10 is "1010" in binary, with complement "0101" in binary, which is 5 in base-10.

Note:

1. 0 <= N < 10^9
2. This question is the same as 476: https://leetcode.com/problems/number-complement/

Solution

buildin function seems still be function

class Solution {
public:
  int bitwiseComplement(int N) {
    return ~N & ((1 << (32-__builtin_clz(N|1)))-1);
  }
};