arrayManipulation

arrayManipulation.js

// brute force
function arrayManipulation(arr, n) {
  const temp = new Array(n).fill(0);
  for (let i = 0; i < arr.length; i++) {
    for (let index = arr[i][0]; index <= arr[i][1]; index++) {
      temp[index - 1] +=  arr[i][2]
    }
  }
 console.log( Math.max(...temp))
}
const arr = [[1,2,100],[2,5,100],[3,4,100]]
arrayManipulation(arr, 53)
//.end/ brute force

// prefix sum method
function arrayManipulation(arr, n) {
  const newmap = new Map();
  for (let i = 0; i < arr.length; i++) {
    const start = arr[i][0];
    const end = arr[i][1];
    const value = arr[i][2]
    if(newmap.get(start) == undefined){
      newmap.set(start, 0);
    }
    if(newmap.get(end) == undefined){
      newmap.set(end, 0);
    }
    newmap.set(start, newmap.get(start) + value);
    newmap.set(end + 1, newmap.get(end + 1) +  (-value));
  }
  let max = 0;
  let itt = 0;
  for (const [key, value] of newmap) {
    itt += value 
    if (itt > max ) {
      max = itt
    }
  }
  return max
}
const arr = [[1,2,100],[2,5,100],[3,4,100]]

arrayManipulation(arr, 53)
//.end/ prefix sum