Geeksforgeeks

Error

×

Leaderboard

Showing:

Handle | Score |
---|---|

@Ibrahim Nash | 5725 |

@blackshadows | 5685 |

@akhayrutdinov | 5111 |

@mb1973 | 4989 |

@Quandray | 4908 |

@saiujwal13083 | 4156 |

@sanjay05 | 3762 |

@marius_valentin_dragoi | 3511 |

@sushant_a | 3453 |

@KshamaGupta | 3318 |

@the_coder95 | 3302 |

Complete Leaderboard | |

Handle | Score |

@shashi1iitk | 398 |

@Suniti Jain | 114 |

@ankish2000nayak | 104 |

@gopalsethlnct | 94 |

@senthil1185 | 90 |

@esmadhan | 90 |

@gyanadipta07 | 89 |

@satwikdash2000 | 85 |

@varunmishra3040 | 83 |

@gamec1634 | 82 |

@pj_1721 | 80 |

Complete Leaderboard |

Given an array of **N** integers, and an integer **K**, find the number of pairs of elements in the array whose sum is equal to **K**.

**Example 1:**

**Input:
**N = 4, K = 6
arr[] = {1, 5, 7, 1}
**Output:** 2
**Explanation:**
arr[0] + arr[1] = 1 + 5 = 6
and arr[1] + arr[3] = 5 + 1 = 6.

**Example 2:**

**Input:
**N = 4, X = 2
arr[] = {1, 1, 1, 1}
**Output:** 6
**Explanation:**
Each 1 will produce sum 2 with any 1.

**Your Task:**

You don't need to read input or print anything. Your task is to complete the function **getPairsCount()** which takes **arr[],** **n** and **k **as input parameters and returns the number of pairs that have sum K.

**Expected Time Complexity:** O(N)

**Expected Auxiliary Space:** O(N)

**Constraints:**

1 <= N <= 10^{5}

1 <= K <= 10^{8}

1 <= Arr[i] <= 10^{6}

Login to report an issue on this page.

We strongly recommend solving this problem on your own before viewing its editorial. Do you still want to view the editorial?

Yes
Count pairs with given sum

...

Please choose 'ReadOnlyMode' if you needn't to 'Edit' the problem e.g. viewing OJ's solution, TestCase Files (TCFs), TimeLimit etc.