1010-pairs-of-songs-with-total-durations-divisible-by-60.js

// 1010. Pairs of Songs With Total Durations Divisible by 60
// https://leetcode.com/problems/pairs-of-songs-with-total-durations-divisible-by-60/

// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

// Runtime: 5484 ms, faster than 22.00% of JavaScript online submissions
// Memory Usage: 37.7 MB, less than 58.87% of JavaScript online submissions

// /**
//  * @param {number[]} time
//  * @return {number}
//  */
// const numPairsDivisibleBy60 = time => {
//   let result = 0;
//   for (let i = 0; i < time.length; i++)
//     for (let j = i + 1; j < time.length; j++) if (0 === (time[i] + time[j]) % 60) result++;
//   return result;
// };

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// Runtime: 68 ms, faster than 84.43% of JavaScript online submissions
// Memory Usage: 38.4 MB, less than 13.89% of JavaScript online submissions

// /**
//  * @param {number[]} time
//  * @return {number}
//  */
// const numPairsDivisibleBy60 = time => {
//   const modded = time.map(n => n % 60);
//   const cnts = {};
//   for (let i = 0; i < 60; i++) cnts[i] = 0;
//   for (let i = 0; i < modded.length; i++) cnts[modded[i]]++;
//   let result = 0;
//   for (let i = 1; i < 30; i++) {
//     let [x, y] = [cnts[i], cnts[60 - i]];
//     if (0 < x && 0 < y) result += x * y;
//   }
//   if (1 < cnts[0]) result += (cnts[0] * (cnts[0] - 1)) / 2;
//   if (1 < cnts[30]) result += (cnts[30] * (cnts[30] - 1)) / 2;
//   return result;
// };

// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

// Runtime: 68 ms, faster than 84.43% of JavaScript online submissions
// Memory Usage: 38.2 MB, less than 21.30% of JavaScript online submissions

// /**
//  * @param {number[]} time
//  * @return {number}
//  */
// const numPairsDivisibleBy60 = time => {
//   const modded = time.map(n => n % 60);
//   const counts = new Array(60).fill(0);
//   modded.forEach(n => counts[n]++);
//   let result = 0;
//   for (let i = 1; i < 30; i++) {
//     const [x, y] = [counts[i], counts[60 - i]];
//     if (0 < x && 0 < y) result += x * y;
//   }
//   if (1 < counts[0]) result += (counts[0] * (counts[0] - 1)) / 2;
//   if (1 < counts[30]) result += (counts[30] * (counts[30] - 1)) / 2;
//   return result;
// };

// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

/**
 * @param {number[]} time
 * @return {number}
 */
const numPairsDivisibleBy60 = time => {
  const counts = new Array(60).fill(0);
  time.forEach(t => counts[t % 60]++);
  let result = 0;
  for (let i = 1; i < 30; i++) {
    const [x, y] = [counts[i], counts[60 - i]];
    if (0 < x && 0 < y) result += x * y;
  }
  if (1 < counts[0]) result += (counts[0] * (counts[0] - 1)) / 2;
  if (1 < counts[30]) result += (counts[30] * (counts[30] - 1)) / 2;
  return result;
};

// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

import { strictEqual } from 'assert';

strictEqual(numPairsDivisibleBy60([30, 20, 150, 100, 40]), 3);

strictEqual(numPairsDivisibleBy60([60, 60, 60]), 3);

strictEqual(numPairsDivisibleBy60([20, 40]), 1);

strictEqual(
  numPairsDivisibleBy60([439, 407, 197, 191, 291, 486, 30, 307, 11]),
  0,
);

strictEqual(
  numPairsDivisibleBy60([
    269,
    230,
    318,
    468,
    171,
    158,
    350,
    60,
    287,
    27,
    11,
    384,
    332,
    267,
    412,
    478,
    280,
    303,
    242,
    378,
    129,
    131,
    164,
    467,
    345,
    146,
    264,
    332,
    276,
    479,
    284,
    433,
    117,
    197,
    430,
    203,
    100,
    280,
    145,
    287,
    91,
    157,
    5,
    475,
    288,
    146,
    370,
    199,
    81,
    428,
    278,
    2,
    400,
    23,
    470,
    242,
    411,
    470,
    330,
    144,
    189,
    204,
    62,
    318,
    475,
    24,
    457,
    83,
    204,
    322,
    250,
    478,
    186,
    467,
    350,
    171,
    119,
    245,
    399,
    112,
    252,
    201,
    324,
    317,
    293,
    44,
    295,
    14,
    379,
    382,
    137,
    280,
    265,
    78,
    38,
    323,
    347,
    499,
    238,
    110,
    18,
    224,
    473,
    289,
    198,
    106,
    256,
    279,
    275,
    349,
    210,
    498,
    201,
    175,
    472,
    461,
    116,
    144,
    9,
    221,
    473,
  ]),
  105,
);

strictEqual(
  numPairsDivisibleBy60([
    14,
    161,
    302,
    232,
    270,
    428,
    155,
    64,
    499,
    400,
    25,
    349,
    434,
    427,
    5,
    265,
    20,
    346,
    463,
    10,
    1,
    163,
    189,
    345,
    390,
    212,
    498,
    281,
    308,
    482,
    447,
    217,
    318,
    239,
    374,
    449,
    298,
    213,
    2,
    230,
    5,
    500,
    300,
    390,
    139,
    484,
    464,
    477,
    111,
    88,
    93,
    198,
    181,
    113,
    393,
    283,
    383,
    205,
    42,
    292,
    335,
    392,
    384,
    268,
    361,
    462,
    413,
    176,
    118,
    111,
    143,
    242,
    166,
    286,
    177,
    52,
    126,
    342,
    415,
    302,
    210,
    48,
    369,
    148,
    209,
    87,
    212,
    53,
    296,
    95,
    97,
    45,
    467,
    47,
    373,
    404,
    43,
    439,
    19,
    64,
    289,
    218,
    268,
    460,
    238,
    456,
    490,
    155,
    429,
    218,
    301,
    225,
    228,
    237,
    453,
    267,
    259,
    327,
    427,
    169,
    176,
    322,
    216,
    451,
    29,
    327,
    404,
    177,
    225,
    44,
    248,
    174,
    287,
    326,
    441,
    354,
    110,
    4,
    226,
    324,
    331,
    158,
    454,
    469,
    354,
    383,
    336,
    211,
    133,
    500,
    233,
    330,
    471,
    327,
    426,
    478,
    195,
    232,
    163,
    312,
    126,
    51,
    161,
    248,
    433,
    348,
    464,
    206,
    480,
    478,
    98,
    354,
    304,
    424,
    338,
    382,
    431,
    379,
    194,
    488,
    6,
    494,
    394,
    469,
    430,
    1,
    207,
    307,
    172,
    47,
    269,
    472,
    415,
    163,
    309,
    68,
    213,
    175,
    343,
    187,
    15,
    232,
    429,
    389,
    373,
    143,
    146,
    88,
    58,
    320,
    116,
    82,
    482,
    125,
    343,
    329,
    115,
    116,
    183,
    389,
    112,
    294,
    74,
    89,
    62,
  ]),
  426,
);

strictEqual(numPairsDivisibleBy60([0, 0]), 1);

strictEqual(numPairsDivisibleBy60([0, 0, 0]), 3);

strictEqual(numPairsDivisibleBy60([0, 0, 0, 0]), 6);

strictEqual(numPairsDivisibleBy60([0, 0, 0, 0, 0]), 10);

strictEqual(numPairsDivisibleBy60([0, 0, 0, 0, 0, 0]), 15);