leetcode-696-CountBinarySubstrings.js

// https://leetcode.com/problems/count-binary-substrings/
// p: string of binary
// r: num int +
// e:
// Example 1:

// Input: s = "00110011"
// Output: 6
// Explanation: There are 6 substrings that have equal number of consecutive 1's and 0's: "0011", "01", "1100", "10", "0011", and "01".
// Notice that some of these substrings repeat and are counted the number of times they occur.
// Also, "00110011" is not a valid substring because all the 0's (and 1's) are not grouped together.
// Example 2:

// Input: s = "10101"
// 10 10 01 01
// Output: 4
// Explanation: There are 4 substrings: "10", "01", "10", "01" that have equal number of consecutive 1's and 0's.

var countBinarySubstrings = function (s) {
  let currentS = 1,
    previousS = 0,
    count = 0;
  for (i = 1; i < s.length; i++) {
    if (s.charAt(i) === s.charAt(i - 1)) {
      currentS += 1;
      //   console.log(s.slice(0, i + 1), i, currentS, previousS, count);
    } else {
      let min = Math.min(previousS, currentS);
      count += min;
      previousS = currentS;
      currentS = 1;
      //   console.log(s.slice(0, i + 1), i, currentS, previousS, count);
    }
  }
  return count + Math.min(previousS, currentS);
};

countBinarySubstrings("11001111101101100");

// var countBinarySubstrings = function (s) {
//   // loop through s to i
//   let count = 0;
//   for (let i = 0; i < s.length; ++i) {
//     const hashmap = { 0: 0, 1: 0 };
//     const charAtI = s.charAt(i);
//     charAtI === "0" ? (hashmap[0] = 1) : (hashmap[1] = 1);
//     // hashmap[charAtI] = 1;
//     // loop through s to i+1
//     for (let j = i + 1; j < s.length; ++j) {
//       //   // hashmap count 0 and 1
//       const charAtJ = s.charAt(j);
//       charAtI === charAtJ
//         ? (hashmap[charAtI] += 1)
//         : (hashmap[charAtJ] = (hashmap[charAtJ] || 0) + 1);
//       //   //// if hashmap[0] === hashmap[1] => count++

//       if (hashmap[0] === hashmap[1]) {
//         ++count;
//         console.log(hashmap);
//         break;
//       }
//       //   //// reset hashmap
//     }
//   }
//   console.log(count);
//   return count;
// };

// countBinarySubstrings("10101");
// countBinarySubstrings("00110");
// 0011
// 01
// 10

// countBinarySubstrings(
//   "1100111110110110011111111111110011001011111111100110111111111101010010011110001111110111101111110101110100001111001110011101011000111011101011111110101100101111110101101101111111001111111000011110110101111111111010101001111100010000001001101001100101111110110111110111111010011001110111101110001011100110011010001011100000001101000011100111111010110101110110000011110110111101010110010101111101011111111111110100110101111101111001101011101111111111100111011011010010110111111101110011011111111110001110110000101111111111101110011111011100010111110011110111111110111000110101011101101011101011011100011101101111110111000111110101100110111111001111110111111101101110011101110111110111111101001111100111010111011110011011100101100101010110001011100110111101111110111111111110010101100100111110101011111010101101101111110111111011011001001111001111000111010111100100110011111111100100111100011111011100001001101111011011110010101110001111010000001111110001011000110110111111000110001110101100111111100011100101000111011101110011111111111011111101111110011110111101110011111101110111110111111101111101011010111110110011011101101111100001000101010110110111011111110111111100110111011001111011100011011100101010111111111101110010101101001111011110111011110011000000110111111111101111010110010010111111100111110111000101111010111011111111111000001011111011110111111111111100100100001101101111110010000111101001111111101011010011110011011111000111010000010110011011011011111111110011111101100010111011010111011111111110101110101001101100010111111001101011011111001000101011111011111011110110101111111011011110101111001010110001101011000110110011111101100111110100101111011001000111111110100111101100101111111010110110011110010010111010111111101111101111101001110011101111110001110111010011011101111100011111111101010101101011111111100110111100111101110110010110111100011111010110011111101101101000110110001010001111011100100111111111011111011111111100101111001111110011010010010111111110110001001101111110011111010110011101111110110010000001111111000110111101101111010111110001011100011111011100100000111111011011010010100110101011001111111101111010111111000101110001011111010110110111111111111101101011100000110101001111010110111100011011110100110111111111111111100011011011110011010011100111111111110110111001110100110111010010110111111111111111110001101111011111110111010001101110111110100111110111111110110111111111011111000000101101101111011011111111111111011111000101111111101111111111111111111111100100111000011010001000110110110111111110101111000110100100001111011100111111010100101101010100000111001111101011001111110111011111011010111111011111011010100111011110001000010111110110111110111011011010001010101101111111101111100010010111101100000110100101111010100111101110111011101001101101111001110111101101111101000110110110111101111011011101010001111010011111110111011011100001111111111111000111010101001110010100011011011101111010111110011111010101101010101111110010101111010111001110000011110100011110110111101001110011101110110101111111000101111010111110111110001111110100100001101010001011111110010110110000101111110110111101000101111011111011001100000111111111101010010100111100111110111100011111101111011111100111110000101111011101001001111001101110100100101101111001111111111000110111111101010110011010010011001000111100010100111111001101111110011111000111101011101111110101111101111010110111111101111011111111111100001101100110110011111111101111111101011010010110110011101000111101111110111111011111111110110011100001111110001111011100111111101011111110100110000110011001011111001001110111011110101101101011011011010011110111011100101011011001110001001101011010111000001101011111111101011001111001001100001111110101001111111011100000111100110101010010111101110111011111010110101111101100111111110011011101011101111110011000110111010110011111111111100111011101111011111101111110011101011100101100100111111111111011011100111111111100101111111001111010100011011111001000010111101111111011111100111110111010101111111011111011010000110010111011011000111111011010000111001010101111101011111010111100011001011110111011101110001000111111111100101100110011011011110111111000100010111111011110100111010111111111001011111111111001111110110010011001111100111011110011111000101101111100110011000010100110111101100111110111101111011111100110011011111011001101010111111111010111111100101101011111111011100001111011011111111011111110010100110000000011000010111011101111101111111101101111001011111010110110101011100001110100101001111001111011101101010011010110111101111110101101111100110111101111111101010000101010010001110111000110101101100101111101101011100101111011111101111011110100001011110110111111111011000111111001111010111011010111000101110011010110010111111101111111110111011111010110111111001010111001110110101011000111110000010001101111111000011010110111100010111110010001110011111001110101001000100111011110000100111101101111010011101011010101101000011111111011101111111101111101101110111011111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1"
// );
// 5718

// countBinarySubstrings("11001111101101100");