Jan 8, 2025 · Dec 12, 2024 · Dec 12, 2024 · Dec 12, 2024 · Dec 12, 2024 · Dec 13, 2024
diff --git a/problems/0150.逆波兰表达式求值.md b/problems/0150.逆波兰表达式求值.md
Original file line number	Diff line number	Diff line change
Expand Up		@@ -502,6 +502,67 @@ impl Solution {
		}
		```

	### C:

	```c
	int str_to_int(char *str) {
	// string转integer
	int num = 0, tens = 1;
	for (int i = strlen(str) - 1; i >= 0; i--) {
	if (str[i] == '-') {
	num *= -1;
	break;
	}
	num += (str[i] - '0') * tens;
	tens *= 10;
	}
	return num;
	}

	int evalRPN(char** tokens, int tokensSize) {

	int stack = (int )malloc(tokensSize * sizeof(int));
	assert(stack);
	int stackTop = 0;

	for (int i = 0; i < tokensSize; i++) {
	char symbol = (tokens[i])[0];
	if (symbol < '0' && (tokens[i])[1] == '0円') {

	// pop两个数字
	int num1 = stack[--stackTop];
	int num2 = stack[--stackTop];

	// 计算结果
	int result;
	if (symbol == '+') {
	result = num1 + num2;
	} else if (symbol == '-') {
	result = num2 - num1;
	} else if (symbol == '/') {
	result = num2 / num1;
	} else {
	result = num1 * num2;
	}

	// push回stack
	stack[stackTop++] = result;

	} else {

	// push数字进stack
	int num = str_to_int(tokens[i]);
	stack[stackTop++] = num;

	}
	}

	int result = stack[0];
	free(stack);
	return result;
	}
	```

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