/* https://www.sololearn.com/Discuss/883078/?ref=app Challenge: Calculate sum of numbers in Pyramid. @luka given pyramid as string, your job is to calculate sum of numbers in pyramid. note: each number in pyramid is separated with white space(s) or new line character. // you can use any language. sample Input: " 3 11 23 3 5 1 31 45 171 -22 14 43 45 271 9" sample output: 653. sample input: " 5 3 8" sample output: 16. */ #include #include // Commonly used characters const char czero = '0'; const char cnine = '9'; const char cminus = '-'; /* Description: Multiply with raised to Credits: @Gordie (JGB) Parameters: int an integer to be multiplied by the result from raising to int to be raised to int exponent to raise Return value: Signed integer of multiplied with the result of raised to the power of */ int mpow(int x, int base, int exp) { int y {1}; while(exp) { y *= base; --exp; } return x * y; } /* Description: Converts a numerical string into its signed integer value. Parameters: std::string a numerical string Return value: Signed integer form of on success, zero on failure ********************************************* NOTE: I wanted to use built-in std::stoi() function for this, but SoloLearn wouldn't let me, it keeps saying stoi is not a member of std. I get the reference and example for stoi from: http://en.cppreference.com/w/cpp/string/basic_string/stol */ int strtoi(std::string si) { int len = si.length(); if(len == 0) return 0; if(len == 1) { // 1 up to 9 if(si[0] >= czero && si[0] <= cnine) return (int)(si[0] - czero); else return 0; // Invalid! } else if(len == 2) { // -1 up to -9 if(si[0] == cminus && si[1] >= czero && si[1] <= cnine) return -(int)(si[1] - czero); } /* flag: 1. This bit is set before loop starts, and will be removed then. On 1st pass, if bit 2 is set we'll skip to the next pass, on next passes we'll check non-numeric characters. 2. Signifies that input begins with a negative sign */ int flag = si[0] == cminus ? 3 : 1; // Exponent for mpow int exp = flag == 3 ? len-2 : len-1; int tmp {0}, sum {0}; for(char c: si) { if(flag & 1) { /* First iteration, skip if it is a negative sign */ flag ^= 1; if(flag & 2) continue; } else { /* Successive iterations, exit function if there's any non-numeric char */ if(c < czero || c > cnine) return 0; } /* Any char in range 0-9 subtracted by 48 becomes the number that the char contain, czero ('0') in ASCII is 48. */ tmp = c - czero; if(tmp) { /* Add number to for positive value, or subtract from for negative value */ if(flag & 2) sum -= mpow(tmp, 10, exp); else sum += mpow(tmp, 10, exp); } exp--; } return sum; } /* Description: Scans a string for numerical characters, and pass the number string to strtoi to be processed, and receive the number. The function summarizes the numbers and returns it to the caller. Parameters: string the string that contains numbers, separated or partitioned by space or new lines. Return value: Signed integer, a summary of all valid integers found */ int sumNumStr(std::string si) { int len = si.length(); if(len ==0) return 0; // Return value int sum {0}; // Temporary buffer for numerical string std::string tmp; /* ms: true when negative sign was found inseq: true when iterating a "probable" sequence of numeric characters. */ bool inseq = false; // Current position int p{0}; for(char c: si) { p++; if(c < czero || c > cnine) { if(c == cminus) { if(inseq) { /* Possible negative value found without space or new line separator */ sum += strtoi(tmp); tmp = c; inseq = true; } else { inseq = true; tmp.push_back(c); } } else { if(inseq) { inseq = false; sum += strtoi(tmp); tmp.clear(); } } continue; } else { inseq = true; tmp.push_back(c); if(p==len) sum += strtoi(tmp); } } return sum; } int main() { std::string s1 = " 3\n \ 11 23\n \ 3 5 1\n \ 31 45 171- - -22\n \ 14 43 45 271 9"; std::string s2 = " 5\n \ 3 8"; std::cout << "First pyramid string:\n\n" << s1 << "\n\nCalculation result: " << sumNumStr(s1); std::cout << "\n\nSecond pyramid string:\n\n" << s2 << "\n\nCalculation result: " << sumNumStr(s2); std::cout << "\n\nThanks for the challenge @luka :-)"; return 0; }

Calculate numbers in pyramid string