for a given array take a empty zero array of size n+2; l— ,r— for 1 based index given;
then diff[l]+=x; diff[r+1]-=x;
then prefix of diff then add original array to pdiff thats answer.
ex - 1 2 3 ,x=4 ,l=1,r=3 diff= 0 0 0 0 0 diff = 0 4 0 0 -4 0 pdiff = 0 0 4 4 4 0 0 ans = 0 0 5 6 8 0 0