Leetcode 1997 First Day Where You Have Been in All the Rooms Solution in java | Hindi Coding Community

 

class Solution {

public int firstDayBeenInAllRooms(int[] nextVisit) {

int rooms = nextVisit.length;

long dp[] = new long[rooms];

int mod = (int)(1e9)+7;

for (int i=1 ; i<rooms ; i++) {

if (nextVisit[i-1] == i-1)

dp[i] = dp[i-1]+2;

else

dp[i] = (dp[i-1] + dp[i-1] - dp[nextVisit[i-1]] + 2 + mod)%mod;

}

return (int)dp[rooms-1];

}

}