djm-1 / CpTasks

CP problem solving on important topics

CpTasks

CP problems of important topics

KATHTHI spoj

1. if not equal char in map then add an edge with weight=1, else weight=0
2. check neighbours and apply 0-1 BFS to find path with min 1's
3. Alternative approach Dijkstra.

REVERSE Codechef

1. for given edge add 0 in x->y direction
2. add 1 in reverse y->x direction (not given edge)
3. apply 0-1 BFS to get a directed shortest path from 1 to n.

PRATA spoj

1. find minimum time when making p number of parathas is possible
2. so monotonic seq of F F F F T T ..... find the first true
3. set max as (p*(p+1)/2) * maximum val in array
4. use BS with predicate function keeping number of parathas as constraint.

SNSOCIAL Codechef

1. Try traversing from maximum value nodes (multisource BFS)
2. Count the number of levels until it exhausts
3. return level-1 (no of edges till deepest node reqd only)

Help king Spoj

1. Classic MST
2. take log of weights and add them
3. cost+1 will give total number of divisors

Game Route CSES

1. Topo sort first

2. dp[v]= edge u→v exists ∑ ​ dp[u],

3. dp[1]=1