add basic-calculator and basic-calculator-ii

Author: freefcw

go/basic-calculator-ii.go

@@ -0,0 +1,70 @@
+package leetcode
+
+import (
+	"fmt"
+	"math"
+	"strconv"
+)
+
+func calculate2(s string) int {
+	result := 0
+	operation := '+'
+	stack := make([]StackItem, 0, 10)
+	hasInitial := false
+
+	for i := 0; i < len(s); i++ {
+		if s[i] == ' ' {
+			continue
+		}
+		if s[i] == '+' || s[i] == '-' {
+			stack = append(stack, StackItem{result, rune(s[i])})
+			result = 0
+			operation = '+'
+			hasInitial = false
+			continue
+		}
+		if s[i] == '*' {
+			operation = '*'
+			continue
+		}
+		if s[i] == '/' {
+			operation = '/'
+			continue
+		}
+		end := parseInt(s, i)
+		num, err := strconv.Atoi(s[i : end+1])
+		if err != nil {
+			fmt.Printf("%s %d %d\n", s, i, end)
+			panic(err)
+		}
+		if !hasInitial {
+			result = num
+			i = end
+			hasInitial = true
+		}
+		// fmt.Printf("%d %c %d\n", result, operation, num)
+
+		if operation == '*' {
+			result *= num
+		}
+		if operation == '/' {
+			result = int(math.Floor(float64(result) / float64(num)))
+		}
+
+		i = end
+	}
+	stack = append(stack, StackItem{result, '='})
+	result = 0
+	operation = '+'
+	for _, item := range stack {
+		if operation == '+' {
+			result += item.number
+		}
+		if operation == '-' {
+			result -= item.number
+		}
+		operation = item.operation
+	}
+	// fmt.Printf("%v %d\n", stack, result)
+	return result
+}

go/basic-calculator-ii_test.go

@@ -0,0 +1,40 @@
+package leetcode
+
+import "testing"
+
+func TestCalucate2(t *testing.T) {
+	tests := []struct {
+		input  string
+		expect int
+	}{
+		{
+			input:  "1+1",
+			expect: 2,
+		}, {
+			input:  "1-1",
+			expect: 0,
+		}, {
+			input:  " 1 + 1 ",
+			expect: 2,
+		}, {
+			input:  " 3/2 ",
+			expect: 1,
+		}, {
+			input:  " 2-1 + 2 ",
+			expect: 3,
+		}, {
+			input:  "3+2*2",
+			expect: 7,
+		}, {
+			input:  " 3+5 / 2 ",
+			expect: 5,
+		},
+	}
+
+	for i, item := range tests {
+		actual := calculate2(item.input)
+		if actual != item.expect {
+			t.Fatalf("%d, expect %d, actual %d\n", i, item.expect, actual)
+		}
+	}
+}

go/basic-calculator.go

@@ -0,0 +1,95 @@
+package leetcode
+
+import (
+	"fmt"
+	"strconv"
+)
+
+type StackItem struct {
+	number    int
+	operation rune
+}
+
+func parseInt(s string, from int) int {
+	if len(s) == 0 {
+		return 0
+	}
+	for i := from; i < len(s); i++ {
+		if s[i] >= '0' && s[i] <= '9' {
+			continue
+		}
+		return i - 1
+	}
+
+	return len(s) - 1
+}
+
+func calculate(s string) int {
+	result := 0
+	hasInitial := false
+	operation := '+'
+	stack := make([]StackItem, 0, 10)
+	stackTop := 0
+	for i := 0; i < len(s); i++ {
+		if s[i] == ' ' {
+			continue
+		}
+		if s[i] == '(' {
+			item := StackItem{result, operation}
+			if stackTop == len(stack) {
+				stack = append(stack, item)
+			} else {
+				stack[stackTop] = item
+			}
+			stackTop++
+			result = 0
+			hasInitial = false
+			operation = '+'
+			continue
+		}
+		if s[i] == ')' {
+			if stackTop == 0 {
+				continue
+			}
+			stackTop--
+			item := stack[stackTop]
+			// fmt.Printf("%v %d\n", item, result)
+			if item.operation == '+' {
+				result = item.number + result
+			} else {
+				result = item.number - result
+			}
+			hasInitial = true
+			continue
+		}
+		if s[i] == '+' {
+			operation = '+'
+			continue
+		}
+		if s[i] == '-' {
+			operation = '-'
+			continue
+		}
+		end := parseInt(s, i)
+		num, err := strconv.Atoi(s[i : end+1])
+		if err != nil {
+			fmt.Printf("%s %d %d\n", s, i, end)
+			panic(err)
+		}
+		// fmt.Printf("%d %c %d\n", result, operation, num)
+		if hasInitial {
+			if operation == '+' {
+				result += num
+			}
+			if operation == '-' {
+				result -= num
+			}
+		} else {
+			result = num
+			hasInitial = true
+		}
+
+		i = end
+	}
+	return result
+}

go/basic-calculator_test.go

@@ -0,0 +1,77 @@
+package leetcode
+
+import "testing"
+
+func TestParseInt(t *testing.T) {
+	tests := []struct {
+		input  string
+		from   int
+		expect int
+	}{
+		{
+			input:  "123",
+			from:   0,
+			expect: 2,
+		}, {
+			input:  "1234",
+			from:   1,
+			expect: 3,
+		}, {
+			input:  "1234 ",
+			from:   1,
+			expect: 3,
+		}, {
+			input:  "",
+			from:   0,
+			expect: 0,
+		}, {
+			input:  " 44 5",
+			from:   1,
+			expect: 2,
+		},
+	}
+
+	for i, item := range tests {
+		actual := parseInt(item.input, item.from)
+		if actual != item.expect {
+			t.Fatalf("%d, expect %d, actual %d\n", i, item.expect, actual)
+		}
+	}
+}
+
+func TestCalculate(t *testing.T) {
+	tests := []struct {
+		input  string
+		expect int
+	}{
+		{
+			input:  "1+1",
+			expect: 2,
+		}, {
+			input:  "(1+1)+(2+2)",
+			expect: 6,
+		}, {
+			input:  " 1 + 1 ",
+			expect: 2,
+		}, {
+			input:  " 1 + (1 + 1)",
+			expect: 3,
+		}, {
+			input:  " 2-1 + 2 ",
+			expect: 3,
+		}, {
+			input:  "2-(5-6)",
+			expect: 3,
+		}, {
+			input:  "(1+(4+5+2)-3)+(6+8)",
+			expect: 23,
+		},
+	}
+
+	for i, item := range tests {
+		actual := calculate(item.input)
+		if actual != item.expect {
+			t.Fatalf("%d, expect %d, actual %d\n", i, item.expect, actual)
+		}
+	}
+}