Ural 1073 square country (DP)

Square country

The amount of money required for a square area with a side length of A is a ^ 2. Now, enter N as the amount of money. You can make up N for the minimum number of places you want to buy.

Idea: DP, DP [I] = min (DP [I], DP [J-I * I] + 1) introduced by the backpack idea ); square is composed of square, so it is I * I, and it is I * I during the cycle.

#include <stdio.h>#define min(a, b) ((a) > (b) ? (b) :(a))int n;int dp[60005];int main(){    scanf("%d", &n);    for(int i = 1; i <= n; ++i){        dp[i] = i;    }    for(int i = 1; i*i <= n; ++i){        for(int j = i*i; j <= n; ++j){            dp[j] = min(dp[j], dp[j-i*i]+1);        }    }    printf("%d\n", dp[n]);    return 0;}