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# include <cstdio>
# include <iostream>

using namespace std;

int main(){
    float eps = 1e-6;
    float a, b, c, tmp;
    scanf ("%f %f %f", &a, &b, &c);
    if (b > a && b > c) tmp = a, a = b, b = tmp;
    if (c > b && c > a) tmp = a, a = c, c = tmp;
    if (b < c) tmp = b, b = c, c = tmp;


    if (abs(a - b - c) < eps){
        printf("NAO FORMA TRIANGULO\n");
    }
    else{
        if (abs(a * a - b * b - c * c) < eps){
            printf("TRIANGULO RETANGULO\n");
        }
        else if (a * a > b * b + c * c){
            printf("TRIANGULO OBTUSANGULO\n");
        }
        else if (a * a < b * b + c * c){
            printf("TRIANGULO ACUTANGULO\n");
        }
        if (abs(a - b) < eps && abs(b - c) < eps){
            printf("TRIANGULO EQUILATERO\n");
        }
        else if (abs(a - b) < eps 
                 || abs(b - c) < eps 
                 || abs(c - a) < eps ){
            printf("TRIANGULO ISOSCELES\n");
        }
    }

    return 0;
}

作者：adnil8130
链接：https://www.acwing.com/activity/content/code/content/221443/
来源：AcWing